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Author Topic: Pathfinder Twin  (Read 3074 times)

Offline Steve Dwyer

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Pathfinder Twin
« on: June 29, 2023, 11:02:17 AM »
I purchased a full size Pathfinder Kit (not 1/2A) from Brodak a couple years back and I'm now interested in possibly converting it to a Pathfinder Twin. I have recently ordered the three sheet PFT plan set from Flying Models. Anyone have a feel for the feasibility of making this conversion using the Brodak kit? I did see that RSM kitted a twin that was once available.

I have read there are some informative threads somewhere in Stunthanger where Gordan Delany described his design thinking and findings that went into creating the twin. If anyone can direct me to this I'd appreciate it. I have reached out to Gordan with a PM, he may be unavailable.

Steve

Online Dan McEntee

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Re: Pathfinder Twin
« Reply #1 on: June 29, 2023, 11:16:44 AM »
  The Flying Models article mentions what kit parts are useful in the twin construction, I think, and you should get a copy of the article with the plan. If you can not find the threads that Gordon participated in through a search, try John Miller through his section back in the vendors corner. John drew up the plan, I do believe.
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Offline John Miller

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Re: Pathfinder Twin
« Reply #2 on: June 29, 2023, 01:56:05 PM »
All the items included in the kit are necessary for constructing the Twin. The only additional elements required are the engine nacelles. The article will probably be included with the plans from Flying Models, but if not, I suggest obtaining a copy, as Dan also recommends.

Gordy has expertise in using IC engines for our model planes, but I prefer electric power for all future twins due to its reliable power delivery. Again, as an engine enthusiast, Gordy likes IC engines, but my choice is electric power

Extend the center sheeting, to one bay on each outer side of the nacelles while keeping the design as a trike-geared one.

Gordy made some minor changes to his new twin last year, including slimming down the nacelles and increasing the height and width of the vertical stab and rudder. For your first attempt, it might be best to stick close to the original plans, though there may be more changes to consider in future versions.

When dealing with twins, it's crucial to pay extra attention to their alignments. Bob Hunt skillfully aligns the nacelles and expertly moves the plane into position, checking all incidents are correct. Gordan consistently performs the same action and their planes demonstrate accurate flight paths.

If you're having trouble getting in touch with Gordan, a phone call is usually the best way to reach him. If you can't find his number, just send me a private message and I'll help you out.

Good luck with your project

John Miller
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Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #3 on: June 29, 2023, 05:51:36 PM »
Dan,

The Flying Models plans store shows the three Gordan Delaney articles listed that were published in Flying Models between 1995 and 2010 on the Pathfinder Twin. I have requested copies of each from Flying Models along with the plans set. Hopefully these will cover the parts details you mentioned. I'll continue to turn stones over in SH, there seems to be a fair amount out there on twins I want to see before I start building. Anything else you can suggest don't hesitate to point me in that direction I'd appreciate it. BTY I have listened to Bob Hunts interview by Sparky discussing twin design.

John,

I'm anxious to receive the twin plans and lay them out next to the Brodak plans for their single engine kit. I did look briefly at some of Bob Hunt's threads on developing twins, electric and retracts. Once I start pulling everything together and have a better grasp of what I'm dealing with I'll give Gordan and probably Bob a call with questions before I start the build. Thanks for the points you have made, I do have Gordan's email address, I'll PM you for his phone if I don't get him by email. This should be a fun build, looking forward to it.

Steve


Online Howard Rush

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Re: Pathfinder Twin
« Reply #4 on: June 29, 2023, 06:18:58 PM »
I have the original if that helps.
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Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #5 on: June 29, 2023, 06:58:46 PM »
Howard,

Are you referring to the twin articles or the plans?

Steve

Online Howard Rush

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Re: Pathfinder Twin
« Reply #6 on: June 29, 2023, 07:38:19 PM »
The airplane itself
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Offline Air Ministry .

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Re: Pathfinder Twin
« Reply #7 on: June 29, 2023, 08:00:38 PM »
 ;)Some stuff there , if you put ' Pathfinder Twin ' in search .
Some unasked for advice ? On the 48 inch wing , I put the crankshafts  seven inches out .
So the Flat Face of the Nacelle is seven odd from the fuse , nacelles to left .

IF you put the NACELLES center equal from the fuselage , YOU end up with the outer a quater or more further & the Inner a quater or so less , On a Profile . Opposite of senseable !
( On the Oriental Wing they stradle a rib ) Id remembered when Id first done them , with the underslung nacelles , just sheeted the underside past the nacelles . Top was two bays.
Behind the spars , that is .
I recon its sensable to do the olde ' rebate the tank ' thingo - Inset it inside the 1/2 sheet , so only ply & Doubler inside of it . This keeps from having tank overhung past needle C / L ,
hopefully giving a better run . Pipes can go through the wood , on the unencumbered side .  :P

This Isnt Dissimalar . Has flown on OS 20s , 25s , MVVS D15s , G 15s , & FP 25 clones . Unreasonably accurate on 70 ft of .018 , at 70 plus ounces . 74 versipon was 38 , 41 with mufflers .
Parental Advice after initial flights " YOU WILL FIT THE MUFFLERS " . This wasnt stated as a question .


                                                     =======================

Offline Air Ministry .

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Re: Pathfinder Twin
« Reply #8 on: June 29, 2023, 08:07:42 PM »
Ive Manadged , with great restaint , to hold off putting a picture of the Mosquito on  !  %^@


How Ive Now Butchered the Navcelles , for um tanks .  That FUEL PROOF STUFF isnt a Bad Idea . PLENTY COATS .

You can see , in the shadow , 1/2 down , 1/2 up , 1/2 back , a hole through . For the Uniflow Pipe . Ends cut at 45 deg ish to airflow .
VENT can be outer corner or ' somewhere ' not thru . The IDEA is to get the whole tank inboard of the spray bar . A tall ask .  >:(

If youve got a real 1/2 sq caRBON TOOB , not THE MUSHY SOFT MODEL SHOP TRIPE , SPAR TO REAR HINGE oops . Or a 1 in. or 1 1/2 in. real firm balsa angle cut at ends & diagonal - as primary load bearer
( Cut to fit from spar to T E angled to end under tailplane - say 1/2  in. + dep at hinge . so can be tapered , side on .  IF you wanna be awkward .  )  and the rests of fuse soft decorative .non structural .  :P

or carbon veil . strips on fuse. sides .

Why the Controls so authoritive is the Side Area , Lesser side aread ones , of the same layout , its deminished & yaw stabilitys nothing like this , So dont be scared of DEEP . Der Flying Ving Fence machine .

The thing IS , you can HAMMER the Controls in Sq's etc , without it ' coming at you ' . Small side area ya gotta be real smooth 7 fly the turns , more like fishing . Dickering them , WHEREAS  .  .  .  .  .
« Last Edit: June 29, 2023, 08:25:43 PM by Air Ministry . »

Offline Steve Helmick

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Re: Pathfinder Twin
« Reply #9 on: June 29, 2023, 08:31:20 PM »
The airplane itself

I have yet to see the Pathfinder Twin fly, Howard. Let me know when & where, ok?  R%%%% Steve
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Online Dave Heinzman

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Re: Pathfinder Twin
« Reply #10 on: June 30, 2023, 03:54:25 AM »
   Steve, I have a Pathfinder twin electric power from a RSM laser kit that I am flying currently. Very happy with mine. I'd be more that willing
   to share with you details about mine. We could get started with a PM here on Stunthangar and go from there.

Dave Heinzman

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #11 on: June 30, 2023, 05:57:10 AM »
Dave,

I'm very interested in finding more about the RSM twin kit. If you can could you provide a view of the plans, I'm curious to see what variations exist between it and the Gordan Delaney design I'm going to build morphing the Brodak single kit. I love IC power but the obvious benefits of electric on a twin has me leaning in that direction. I built a Primary Force electric with good results two years back using the RSM system so going electric is not foreign to me.

I'll no doubt have many more questions than I already have, let me absorb the plans and the FM articles and I'll start bugging you.

Steve

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #12 on: June 30, 2023, 06:00:16 AM »
Howard,

Can you elaborate a bit more on the model's history and performance/power etc. and some pictures would be helpful.

Steve

Online Howard Rush

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Re: Pathfinder Twin
« Reply #13 on: June 30, 2023, 02:23:31 PM »
It has two OS .15FPs, muffler pressure, APC 9-4s, which Gordan may have modified. It burns YS 20-20, 1/4 oz. more in the right tank than in the left. I can give you more information when I get back from a trip. John knows more of the history, and Gordan knows everything. It is a very good stunt plane.
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Online Dave Heinzman

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Re: Pathfinder Twin
« Reply #14 on: June 30, 2023, 06:47:25 PM »

  Hi Steve, still learning how to attach pictures with post. not sure how helpful this will be.

  Dave

Online Howard Rush

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Re: Pathfinder Twin
« Reply #15 on: June 30, 2023, 07:32:07 PM »
Airfoil looks inaccurate. 
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Offline Air Ministry .

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Re: Pathfinder Twin
« Reply #16 on: June 30, 2023, 10:56:33 PM »
Canae be finding a drawing , bot ;

Quote
Here's another vote for Gordon Delaney's Pathfinder Twin.  I was so impressed by it that I got the plans and bought two OS FP15's and I'm building one.
I usually don't get very excited about profiles.

When I flew it I was expecting it to be pretty good because a lot of guys like Bob Whitely flew it before I did and Bob was really impressed and He doesn't impress easily.  Then I flew it and truly couldn't believe it!
It did everything as well as anything I've flown (and I've flown some pretty good airplanes).

Of course it was in wonderful trim...no less would be expected with one of Gordy's airplanes, but it flew like a larger very competitive competition stunter!

If you really want a profile and can deal with two engines (a little more work), I really believe there is nothing better.  Actually it's an easier build than most also.

Randy Cuberly

& a Twinatation .

Quote
Gordan's usual build tips/mods are:
1.  Set the hinge to hinge measurement at 16" (this may require cutting a bit off of the end of the supplied Brodak fuselage)
2.  Build the stab and elevator from 3/8" material.
3.  Sand a mild taper into the tips of the stab and elevator
4.  Keep it light.
5.  Build it straight.

Also, I would recommend that you laminate two 4x36 x 1/4" pieces using 30min epoxy for the fuselage.  Much stiffer than a single 1/2" plank.
Brent Williams »

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Quote
Brent has most of the changes right except one.

I only use 3/8 stab on my .15 twin.
I use 1/2 in stab and taper it to the tips, and sharpen the leading edge more than the plans show.

Gordan Delaney

A bit edited , from : https://stunthanger.com/smf/open-forum/brodak-pathfinder/

If you find a 5.000 year old plank of 1/2 , or one thats been in the sun for 10 years , or SOL:ARBO 1974 first Box of 48 in x 4 in available  , therell be a few light seasoned stiff quater grain
kiln dried sheets in it , thatll be SATRONG & LIGHT . In times of yon , where there was natural organic Balsa ! a tree that took ten years to grow on one side of the valley was way stronger
than its more favoued cousin that grew in a year or two with lots of sun & water . Main Thing is SEASONED . ' fresh ' balsa is useless , after 18 months its changed its stripes considerably .
The old Bend over the Knee Trick , and the grab ends ( Cautiously but firmly ) and TWIST to find if its got good torsional strength . The WEIGHT is NOT the PRIORITY . Its ridgidity is .
THIS is primarily from its growing location and its treatment since felled & Seasoning / dehumidifying . It required expertise & a bit of science . Not all Balsa is created Equal . Or milled equally .

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #17 on: July 01, 2023, 09:11:40 AM »
Howard,

I tend to agree on your point, it's almost a bit too pointed and leaning toward the old Chief airfoil too thin as it approaches the trailing edge. I'm curious how it compares to the Brodak Pathfinder print. Also wonder how it compares to the Eric's RMS airfoil? I'll check on Brodak's and get back.

Bob did fly Gordan's PFT and was very impressed with it's handling. I think Bob's "test bed" model was a foam wing I wonder how his airfoil compared.

Good observation.

Steve

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #18 on: July 01, 2023, 10:02:15 AM »
Dave,

Here's the dimensional configuration of the Brodak Profile rib taken from the kit. Can you provide comparable dimensions from the prints you have especially the height of the rib. It does appear the dimension from the spar to the leading edge varies somewhat???

Thanks,

Steve

Online Ara Dedekian

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Re: Pathfinder Twin
« Reply #19 on: July 01, 2023, 11:43:09 AM »
Howard,
Also wonder how it compares to the Eric's RMS airfoil?
Steve

      Steve,

         Here's a rib from my RMS Twin Pathfinder kit. The plans are John Miller's as in the previous post and the rib is dead on to the plan. Height of the rib is 2".

     Ara

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #20 on: July 01, 2023, 02:34:46 PM »
It's my takeaway the Brodak Pathfinder Single kit airfoil configuration is identical to the Gordan Delaney/John Miller Cad print used by RMS for their twin. There's also been good reports on the performance of the RMS Twin as well as the Delaney model Bob Hunt flew and said he was impressed with.

I'm going to proceed with modifying the Brodak single kit according to the Miller prints. I'll have more questions as I move along.

Thanks,

Steve


Offline Brent Williams

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    • Fancher Handles - Presented by Brent Williams
Re: Pathfinder Twin
« Reply #21 on: July 01, 2023, 04:33:38 PM »
Gordan constructs his own Pathfinder wings differently than the method shown on the Brodak kit plans.  He uses a fully molded balsa leading edge cap that goes back to the spar. 
His leading edge is an ellipse, or closely resembles an ellipse in overall shape from the front to the high point of the wing.  This has been his method for at least 15+ years, and probably more.  The rib template attached below is Gordan's rib template.
In our local club here in Utah, there are several well trimmed pathfinders representing all of the various iterations of leading edge shape and construction methods.  Whether they were built from the Brodak kit or from scratch, they all have something in common....They all fly great!
« Last Edit: July 02, 2023, 02:42:39 PM by Brent Williams »
Laser-cut, "Ted Fancher Precision-Pro" Hard Point Handle Kits are available again.  PM for info.
https://stunthanger.com/smf/brent-williams'-fancher-handles-and-cl-parts/ted-fancher's-precision-pro-handle-kit-by-brent-williams-information/

Online Howard Rush

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Re: Pathfinder Twin
« Reply #22 on: July 01, 2023, 05:02:59 PM »
I'll have more questions as I move along.

Such as, “Why won’t this airplane turn a sharp corner?”
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Online Dan McEntee

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Re: Pathfinder Twin
« Reply #23 on: July 01, 2023, 06:42:43 PM »
It's my takeaway the Brodak Pathfinder Single kit airfoil configuration is identical to the Gordan Delaney/John Miller Cad print used by RMS for their twin. There's also been good reports on the performance of the RMS Twin as well as the Delaney model Bob Hunt flew and said he was impressed with.

I'm going to proceed with modifying the Brodak single kit according to the Miller prints. I'll have more questions as I move along.

Thanks,

Steve

   I would have been surprised if you found something else because I think John drew or approved all the plans that I know of out there. John will correct me if I'm wrong, but he  sells the plan through his own company, did the plan and collaborated with Gordon for the Flying Models article, and again worked with Gordon and Eric Rule on the RSM kit. I got a set of plans from John, and has some templates glued up from copies, and still plan to build one in the future.

  Type at you later,
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Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #24 on: July 02, 2023, 07:02:59 AM »
Such as, “Why won’t this airplane turn a sharp corner?”

Yes that a good starter question.  In a video the "test bed" models did not appear to make a tight radius but obviously has outweighing benefits. It appears to track very well in the 5.0+ sec range and stays right where it is supposed to be throughout the pattern.

Could it be a bit too nose heavy even with the two .15 engines? The flap root chord to long or just too much relative throw? How does the single compare in flight?

Steve

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #25 on: July 02, 2023, 07:06:36 AM »
    I got a set of plans from John, and has some templates glued up from copies, and still plan to build one in the future.
   Dan McEntee

Dan, Will you go electric or IC and the basis for your decision?

Steve

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Re: Pathfinder Twin
« Reply #26 on: July 02, 2023, 08:47:12 AM »
Dan, Will you go electric or IC and the basis for your decision?

Steve

    Definitely IC, mainly because I don't want to have to invest in the infrastructure needed for electric at my age. I Have engines, venturis, tanks and everything I need for power already stashed away, just need to "do it" as they say in the commercials. I'm a gear head at heart, and me and engines get along just fine.

    Type at you later,
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Offline 944_Jim

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Re: Pathfinder Twin
« Reply #27 on: July 02, 2023, 10:22:56 AM »
I'm a sucker for twins! This twin Pathfinder is drawing me in like a toy boat in a bathtub following around draining water.

The Brodak 1/2A Pathfinder was mentioned earlier in this thread. So I have to ask...would similar treatment to the Baby Pathfinder yield an interesting take for a fringe-following outlier?

I've already scaled a TC-Two down to 35" for a pair of Medallion .049s (or a pair of BigMig .074s), however this Pathfinder sure looks a lot more attractive. The TC-Two had been selected because it just looked easier/faster to hand-cut.

Concerning the FM articles...anyone know the particular year(s)/months(?) they appeared? I'd like to review the articles regarding the full-size ones to see how that may apply to a Baby Pathfinder Twin?

Thanks for y'alls input.

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Re: Pathfinder Twin
« Reply #28 on: July 02, 2023, 11:01:53 AM »

(or a pair of BigMig .074s)

      Ever since this topic began, I've been toying with calling John Miller for a set of scaled plans for a Norvel .074 Twin Pathfinder. Every time that engine gets mentioned on here, comments come in stating it's one of the most reliable engines out there. I can attest to that with my Sig Hummer/Norvel .074. RC sport flyer. Resisting electric C/L($$$), the Norvel .074 seems the safest choice for the least trouble free glow power for a small twin. I came home from Brodak with a set of his 1/2A pathfinder plans and thought about powering it with the .074 but the rules limit 1/2A Stunt to .061. Brodak's is the only place I'd get to compete with it so I'd have to settle for profile stunt.

    Ara

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #29 on: July 02, 2023, 11:09:41 AM »
Concerning the FM articles...anyone know the particular year(s)/months(?) they appeared? I'd like to review the articles regarding the full-size ones to see how that may apply to a Baby Pathfinder Twin?

Jim....

Flying Models:   March 1995,   May 2009,  August 2010   They are available for $5.00 each on the FM website. If you want, go to Flying Models Plan Store,
Search Pathfinder Twin and the offerings will show along with the print set.

Steve

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #30 on: July 02, 2023, 11:17:28 AM »
    Definitely IC, mainly because I don't want to have to invest in the infrastructure needed for electric at my age. I Have engines, venturis, tanks and everything I need for power already stashed away, just need to "do it" as they say in the commercials. I'm a gear head at heart, and me and engines get along just fine.

    Type at you later,
     Dan McEntee

Dan,

I built an electric Primary Force two years back and it all went well as my first experience powering with electric. I had to invest in the "infrastructure" as you say and it wasn't cheap but it was on my bucket list...  Plus I'm leaning toward elect because I don't have the IC power in the sizes I'd need and have to buy these OS LA15 or 20 size engines and they are not cheap on ebay.

Steve

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Re: Pathfinder Twin
« Reply #31 on: July 02, 2023, 12:13:50 PM »
Could it be a bit too nose heavy even with the two .15 engines?

Tail is built pretty light, but there's an ounce of lead on the nose.

See the leading edge?
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Online Dan McEntee

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Re: Pathfinder Twin
« Reply #32 on: July 02, 2023, 03:11:47 PM »
Dan,

I built an electric Primary Force two years back and it all went well as my first experience powering with electric. I had to invest in the "infrastructure" as you say and it wasn't cheap but it was on my bucket list...  Plus I'm leaning toward elect because I don't have the IC power in the sizes I'd need and have to buy these OS LA15 or 20 size engines and they are not cheap on ebay.

Steve


     When I read the article and then follow up feed back from top NATS pilots that flew the model, that was all the motivation I needed to put together the power packages. I am always looking for a deal, and and when one presents itself, I usually can take advantage of it. I have always wanted to build a twin and have several options for sizes in mind, Everything from the twin 1/2A model that Pappy DeBolt published in Air Trails that is OTS legal, to TC Two that has been mentioned already, to Jack Sheeks' Mosquito, and then the Pathfinder twin. I have plans for all, a kit for the Mosquito, engines for all, including a left handed Enya .30 for the Sheeks Mossie to try counter rotating props, and three sets of engines to try on the Pathfinder. You used to be able to find FP-15s pretty cheap around these parts, so I would pick them up when I say them I grabbed two of the Magnum .15s almost as cheap when I saw that some one was selling them out and got needed venturis and such from Jim Lee already, and have had some LA.15s in the foot locker also. All of these have really close mounting holes so experimenting with different engines won't be too difficult. If there is anything that I have learned in my time on this rock is that NOTHING EVER get cheaper!! Things were much cheaper just three years ago, and were much cheaper yet 13 years ago when the article came out!! I have been a life long model airplane builder with occasional forays into restoring and racing vintage dirt bikes. I've worked two and sometimes three jobs to accumulate stuff that I wanted to do in retirement, and bought stuff back when it was cheap and easy to find. Now that I have gotten to retirement and got some important body work done, it's time to start working on having fun. Some I may not have enough time to get to, but if I WANT to do that project or this one, I just go pull the stuff off the shelf. I flew electric R/C sailplanes a lot back in their early days, and even then I could see that technology didn't stand still. Nothing I have from back then is usable, but engines I bought back then are still serviceable. Technology still does not stand still with electric stunt and it is more complicated. Some guys get the idea that it is just like plugging a battery into a power drill and go flying, but they find out there are electronic buggaboos also!! I just don't feel the need to go through the learning curve that I see other guys going through, when engines and what they need is something I understand and have pretty good success with, at least enough to keep me happy.
  Type at you later,
    Dan McEntee
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Online Dan McEntee

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Re: Pathfinder Twin
« Reply #33 on: July 02, 2023, 03:21:09 PM »

Could it be a bit too nose heavy even with the two .15 engines?

Steve

    Those two engines are pretty light by themselves, especially if using OS FP or LA engines and they are not mounted out on the nose. The mass of the engine is about 1/2 way from the nose to the leading edge. And the props are only 9" in diameter, and then there is the theory that the prop wash going over the flaps directly has a positive effect. You have moved the spinning prop arcs closer to the balance point also. The original is a proven single engine design, and it was designed by a guy with a proven track record in designing good flying twins! I would venture to say that if you have trouble with this airplane turning, it probably ain't the airplane's fault.
    Type at you later,
     Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #34 on: July 02, 2023, 04:12:57 PM »
Dan,  thanks your response is encouraging.

Can anyone identify the builder of the "Twinatation" in the Air Ministry post number 16 above? Very pretty airplane. I'm curious how the tail dragger gear configuration worked out with a 54" span wing. Like to know the dimension of the wheel stance.

Steve

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Re: Pathfinder Twin
« Reply #35 on: July 02, 2023, 08:35:47 PM »
Dan,  thanks your response is encouraging.

Can anyone identify the builder of the "Twinatation" in the Air Ministry post number 16 above? Very pretty airplane. I'm curious how the tail dragger gear configuration worked out with a 54" span wing. Like to know the dimension of the wheel stance.

Steve

No

Bother

Oh Dear .

TAIL DRAGGER = Undercarrage = lots of DRAG . Team Race ' Discus ' ish wheels a must , Id Think . Ballon on these , you feel the ' nose down trim ' . Affects Turning . And they flip on Rough Grass iusually, landing .

LAUNCHING , Mean Viciuos Swing as the Tail Lifts . SO NEED TO LAUNCH TAIL UP , it'll stay up , if the launchee holds it right aft between fingers . Youll need the Old 15 Deg. fwdof C.G .

CORRECT TRACKING . Axles Circle aligned . NO DRAG on inner wheel to axle ' Minimum on outer - to tend to hold lines useable .
HAND LAUNCH instructions are Stiff Right Leg , one Step ( of Left ) Banked Out as if circle were opposite . Plane sorts jumps & sits flat - Lines Steady . Straight , Flat , Hesitated and other things . . . .
It Swings LEFT .
HARD .
ROLLS
usually three times ,
by the time it gets to where you were standing ,
inverted
On A Good Day it just bores in flat , inverted . Ten Yards behind you .
 :P   >:(   %^@   cetra et so on .



 LL~   LL~   LL~  GUARENTEED . Also Similar trying to recover UPWARD from Inverted on the Outer . They can spin , chew the lines , pull off the nacelle and break themselves BEFORe they hit the Ground !  %^@

Therefore ; A GOOD Nose Leg , Maybe Cussioned to use as a ' Hit First ' life saver . A Tube installed say 20 Deg. slope , with a leg with wire ' spring ' soldered - going back to align it . Just a straight 14 G / 2 mm
wire , say 5/8 bound & soldered to nose gear leg , going back two inches . to a THING . or a flat loop to a pin / screw . In Hardwood Insert . A ? thing onna da bottom , so Wheel is Central to the LEG avoid tourque twist .
« Last Edit: July 02, 2023, 08:57:01 PM by Air Ministry . »

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Re: Pathfinder Twin
« Reply #36 on: July 02, 2023, 08:39:41 PM »
Likeum This .



Any Twin the U/C drag is way noticeable . Leg Fairing's'd reduce that .



Like a wooden bi plane strut fairing .

You could have it so the wheels / legs , drop say 15 m.m. after liftoff . freeing themselves to rotate back flat . Bottom of wheels still below the timber , so they can rotate on landing . even with trike gear .


ANYWAY the alignment & free spinning of the gear , checked rolling , lines out - attached . So it dosnt crab , scrabble or grab will youd think perhaps be necessary . Grass is more forgiving there . But can flip it ,
maybe wheel spats / pants .

Summary : a good surface and ' set up ' and your fine .

Any Neglegance , and it can BITE .

theres something in the side area displacement , too . That Mosquitos worst , if misshandled . Has a lot of ' side windage ' Fwd , least aft . Gave up undercarrages , as weights borderline ( 60 Oz ) on all ,
so noticeable & detracts significantly from ' free running ' performance . So try to keep it clean , tidy , and light . Taitanium Wire ?  VD~
« Last Edit: July 02, 2023, 09:06:02 PM by Air Ministry . »

Offline Gordon Tarbell

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Re: Pathfinder Twin
« Reply #37 on: July 03, 2023, 06:49:13 AM »
Bob Duncan built the twin Imitation. It is powered by two LA 25's . Bob is retired from building and flying. I currently own the twin Imitation you see in the picture It flys very nice.
Gordon Tarbell AMA 15019

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #38 on: July 03, 2023, 07:24:16 AM »
Gordan,

I assume it's a RSM kit? What's your take on the fuse mounted landing gear? I'd probably go back to silk instead of Polyspan because of the stickers that pop up at the park I fly at.

Steve

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #39 on: July 03, 2023, 08:11:57 AM »
Gordan,

DUH....Imitation Twin not a Pathfinder, I re read your post and see the tail is definitely not a Pathfinder. He still modified the gear from Ted's wing gear designed Imitation to fuse mounted.

Steve

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Re: Pathfinder Twin
« Reply #40 on: July 04, 2023, 10:16:46 PM »
The 6 in pitch props were worst for swing . More Manadgeable on 9 x 4s . STILL , the point is , use caution - Dont be slapdash - at LAUNCH with a twin tail dragger . They can BITE .

best to have a bit of crumple zone or give , so a knock dosnt smash anything , just bends a leg . As stated , at OVERWEIGHT the gear drags quite discernable in respect to the manouvres .

p.s. was timed around 90 mph on 60s , 8x6s & 20 % nitro , Veco 19s , in SPEED . The blue thing .

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #41 on: June 04, 2024, 04:42:01 PM »
The Pathfinder Twin Painting continues

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #42 on: June 04, 2024, 04:43:48 PM »
Four files are too large.

In case someone asks why the multiple holes in the engine bearer...interchangeable engines, either an OS La 15 or 25. The outer holes are to secure an interchangeable plate that won't be required as it turns out.

Steve

Offline Shorts,David

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Re: Pathfinder Twin
« Reply #43 on: June 04, 2024, 08:23:36 PM »
Can't find my picture of it, but Fred Constantine in California flies an electric twin Pathfinder. I'll look for my pics when I'm home.

Offline Paul Wescott

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Re: Pathfinder Twin
« Reply #44 on: June 05, 2024, 05:45:30 PM »
This is how you twin a Pathfinder.

By Warren Walker.


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Re: Pathfinder Twin
« Reply #45 on: June 05, 2024, 07:51:28 PM »
And I was gunna say those OS 20 / 25 maxes are good engines for twins . Ran em 70's with no nitro , balmy stable weather theyed opperate good . light & well behaved . The old 15 lookalikes are ' tested ' on 9x4s at good revs . Yet to authenticate this . But theyre about 4 Oz weight . If your going ultra light . the 25s are likely best if you wanna use the full 70 foot lines .

Like youre Path F-82 Finder . Cunning idea . Think outside the box .

Offline Chris McMillin

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Re: Pathfinder Twin
« Reply #46 on: June 06, 2024, 12:21:16 AM »
I flew it two rounds at a contest at Whittier about ten years ago, I think 5 of us flew it and it turned so hard with hardly any handle input I was 8 feet high half the time. Turned good, I thought.
Chris…

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #47 on: June 06, 2024, 06:46:16 AM »
Anything silver is always a challenge, prime, sand, prime sand and onward. Today the red trim goes on, more to come.
I've made an effort to build it light unlike some of my earlier models. Like sparky said you'll end up with a lumber wagon if you build with heavy wood. I'm anxious to see how the two 15s will handle it. The 25s are mounted 3/8" rear of the 15s but still I'd prefer not to add the extra weight to the nose.

Offline Steve Dwyer

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Re: Pathfinder Twin
« Reply #48 on: June 07, 2024, 09:17:19 AM »
Red trim added.


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