Hi Bob
Can you talk a little about the retracts? Are they off the shelf R/C retracts, are they electric or air driven retracts? As I get more into electric planes it seems that retracts are a natural addition and I would like to leverage off your work. I am also interested in how the Hubin timer will work in this plan.
Andy Borgogna
Glad to see this project back on the front burner. I've been running Hyperion batteries all this last year. They have been great batteries!
Rob
I already have that 2 ounces scheduled for something else in my new plane.Fluorescent paint?
C'mon Howard ... it must be invisible feet!
methinks that would be hidden feet ;D ;D
Randy
(snip)I would guess that your Battery Eliminator Circuit(snip)
OK, I am new to all this, but I just ordered a FM-9 retract timer and if I understand correctly I will need an external BEC to provide enough power to drive the retracts. No problem there, but who makes the external BEC and which unit should I get. I am serious about going down this path with the Spitfire.
Andy
Hi Paul,
Really? Does the BEC output voltage of the Schultze collapse under the load of the retracts?
"Is it the real voltage or did it come out of a bottle? ...Only his voltmeter knows?"
Now I have to get Hunt to hook his up and try it.
Castle sell a nice switching circuit BEC that will do the trick nicely.
Merry Bah Humbug to All!
Dean P.
With all the extra power we have available, the drag of the fixed LG is not a big problem...Even the extra battery capacity required, which is the number I'd be concerned about, is not a big deal. Also, the drag of an imperfectly fitting fairing for the retracted gear may offset a significant amount of fixed gear drag. If anybody would like to see how much drag his round-wire, exposed-wheel gear has, he could send me a stamped, self-addressed email message.
Even the extra battery capacity required, which is the number I'd be concerned about, is not a big deal. Also, the drag of an imperfectly fitting fairing for the retracted gear may offset a significant amount of fixed gear drag. If anybody would like to see how much drag his round-wire, exposed-wheel gear has, he could send me a stamped, self-addressed email message.
I admit i have not read every post but i am curious where the engines will be ?
Quaint CAD system.
Quaint CAD system.Okay Gang ...
I have two drawing boards and will gladly sell one of them! >:D
I know that CAD is the way of the future (Just like electric...), but I still enjoy drawing those long, swoopy lines on paper and then being able to look at the resulting drawing from many different perspectives to get an idea of what it will really look like. In other words the analog method of drawing still has its place.. y1
Recently I've been working with Bob Kruger, who is becoming very accomplished at making CAD drawings with the swoopy curves intact, and we've worked out a method of producing drawings in which I send him very accurate pencil drawings and then he scans them in and overdraws in CAD. The first of these that the modeling (or stunt) public will see is the Gene Schaffer designed "Oosa-Amma" (The original Stunt Machine - the one before the published one). Bob is doing the CAD plans and we will donate them to PAMPA to run along with an article on the Oosa-Amma that I am writing. I'm building an Oosa-Amma right now to provide some construction photos to go along with the article. I also have quite a few photos of the original plane, which I have just returned to its owner, Andrea Moore. Her husband, Ray Moore obtained the original and had it in his basement at the time of his passing. Andrea graciously lent the model to me to measure and draw.
The Oosa-Amma is Classic legal and is large enough (approximately 625 square inches) to utilize one of Randy's PA 40 R Ultra-Lite engines, and that's exactly what is going in mine. I know that it is politically incorrect to write about glow stuff here... Tough. In fact, I'll post a couple of photos of the original one that Gene designed in 1969. I'll also post a photo or two of some of the components of the one I'm building.
Later - Bob
I know that it is politically incorrect to write about glow stuff here... Tough.LOL!! Being "Second in Command", I can allow a "touch" of lee way on topics in a thread! LOL!! I can't really figure out what politically correct means, anyway.....
Okay Gang ...
show of hands here: how many of you working in CAD find that the swoopy curves you draw are somehow limited by what is easy to do with your drawing package?
later,
Dean P.
Just a couple of the many 'swoopy doodles' in my puter. I use a drawing program not CAD. Can do very accurate drawings such as the Elroy's template for motor mount with cooling holes.
Hi Dean
There is no limit to drawing curves, all curves, elipses etc.. and lines can be drawn in AutoCad and many many other CAD and Draw programs, I have very nice curves in my Eliptical Ships
Regards
Randy
Pretty quiet here, what's the latest Bob?
Hi Wayne,
I just talked to Bob today. His plate is too full right now to work on his twin as much as he would like to. Between working on our PAMPA STUNT NEWS MAGAZINE around 45 hours per month, and running two businesses, I can't imagine where he finds time to even touch his own models. But knowing Bob, he will somehow find the time and provide us with another progress report soon. I think we all owe Bob a lot for making the PAMPA SN such a great magazine that we all enjoy throughout the year. I am always amazed at how much time he donates to the PAMPA project on our behalf. Without his 45 hours per month volunteer work we would not have such a wonderful periodical and Bob would have the time to finish his twin much sooner.
Regards, H^^
flying under too low ceingCLP** BW@
http://www.youtube.com/watch?v=hRYlEeyy424
http://www.youtube.com/watch?v=l74uqL3_dAw
and over too high ground :- )))))
http://www.youtube.com/watch?v=wyzB1ul6R3c
Bob,
But I miss the tail cone pipe exit on the bottom. It looked cool. :'(
Yes ...
Mongo like!
Dean
Obviously there will soon be a very sleek and stylish nose cone added to this ship.
Hi Bill,
Isn't there always a STORY ?
Dean
You're BOTH Mongos, ceptin' Dean-O is a little closer to the ground!A low CG is good ... better handling, you see.
Ward-O
Wait a cotton-pickin' minute here!The center motor just needs a C-rot prop. Simple?? Yes I am.....
I thought the whole point of the twin was to eliminate the trim problems caused by spiral airflow and GP with couterrotating props.
A trimotor ... SIGH n~
later,
Dean P.
I sure loved the way his Profile Pathfinder Twin flew!
Bobby is so great. I talked to him at VSC a little. Too many people at times to converse. He told me he is completely sold on electric. I guess being able to fly in the neighborhood at 0700 hours is good. Yes he won Classic again and after the banquet he stated he was told to not bring the same plane again. I think he said it was 9 years old. After my experience again with needle settings maybe electric might be the way to go for all out competition. But, I still like the sound of a good engine run in stunt. I was kind of startled when the electric entry in Classic cast a shadow as it flew over head(really I was outside the circle). I didn't even hear the prop noise. But, Bob asked if I had been keeping up on this twin build. That is why I am here reading it again on Sunday morn before Church. Also waiting for the final result of his Oosama plane(chech spelling) could be Usaama. He is a power house and his little talk after receiving the Keeper Of The Flame Award was inspiring.
Thanks, Keith:anybody in their right mind can see that its a modified fancherized twister,, I mean come on! really,, sheesh,,,, LL~
Yeah, I'll be very upset if someone asks me if it's a modified Nobler... :-\
Bob
Hi Howard:
That might have something to do with my cousin, Bram Stoker... :-\
Bob Hunt
PS: Thanks, Doc, for the kind words. Was great to see you again in Tucson. - Bob
I'm pretty sure that I'll be happy to stay with twins for a while, although I have given some thought to a tri-motor set-up with counter-rotating props on the motors in the nacelles on the wing and contra-rotating props on two motors in the fuselage (four motors and four props...). Of course a dual pusher-puller contra-rotating setup on the wing (front and back...) one contra-rotating setup in the nose of the fuselage (if you are counting, that would be ten separate motors and props...) might be a doable option.
It was meant as a compliment....
Most twins I've seen were scale style jobs...... the french twin at the worlds.. windys' twin's - and a few other twins which escape my mind ( Gordon delaney perhaps... I cant QUITE recall.. ) I think it was called Too much - or Too trouble... Soryr for being vague on that.
What i mean was classical AMA Stunt ships have flowing lines and stylish cue's this is the first time I've seen a twin that takes its styling lines from classical ship shapes. - Very impressive.
Bob,
What's the little note pad for on the bottom of the holding fixture?
I do not see any need to put CF over the silkspan on the covered wing. I do, however, carbon the entire wing prior to covering with silkspan. I remove the carbon from the open bay areas by sanding against the edges of the cap strips and the wing framing (LE and TE sheeting) to insure that there are no "sharp" edges that might later cut though the silkspan. The carbon adds very little in weight and it adds tremendous strength. I know that others do not believe that the carbon adds much strength. I feel that it adds a lot of torsional rigidity to the airframe. I also feel that all the planes I've covered with the .2 ounce carbon mat fly better in the wind than did models that I've owned that were not carbon covered. The carbon adds much stiffness.I was thinking a layer of cf on top of the silkspan would add a lot of puncture resistance for a small weight gain. I recently got careless while handling one of my models and poked a hole in it, and it is covered with polyspan (regular).. I tried the lite version of polyspan a while back after talking with you, but I didnt like it. Took too many coats to get it filled, seemed like more work for little if any weight saving. Why did you choose silkspan for the twin vs polyspan ?
Later - Bob Hunt
I'm pretty sure you would be sorry that you covered over silkspan or Polyspan with carbon.Why is that, because of the extra weight ?
When the wheels go upIf the judges were managing to be completely objective, retracts would only make a difference in as much as they affect the aerodynamics of flight (and if they make it worse -- oops). I suspect that if you get any points from the "wow" factor, it'll wear off as the judges get used to seeing the wheels go up.
Scores should erupt
But they’ll say I’m a clown
If they don’t come down
If the judges were managing to be completely objective, retracts would only make a difference in as much as they affect the aerodynamics of flight (and if they make it worse -- oops). I suspect that if you get any points from the "wow" factor, it'll wear off as the judges get used to seeing the wheels go up.
I'm sure you're already thinking about this, but it sure seems that you'd want to think carefully about when you want the gear to go up. Too soon and the "wow" factor is of entirely the wrong kind. Too late and you don't get nearly as much "wow" as you'd like. Just right, from a purely aesthetic point of view, would be to start a slow retract right as the wheels leave the ground -- but that really flirts with 'too soon' if anything delays takeoff.
I'd be concerned with the retracts messing up the airflow when I'm trying to achieve a smooth takeoff and level flight (actually, I'm a rank beginner -- I can't reliably achieve level flight yet, so retracts would just give me something to blame other than myself). At worst, you could time things so that the wheels went up after your two laps of level flight, but that would certainly remove a lot of the "wow". At best, any bobbles from the wheels going up would be slow, and could be timed for the climb phase of the takeoff where they'd hopefully get subsumed in the overall climb.
It sure seems that with a wide selection motors and props, that you should be able to get more braking in he down lines. You may need to go with some combination that's too aggressive at braking when the gear is down.
And I didn't want to say anything that would stop you: I'm just mentioning points that you may have not yet pondered, or have skipped over lightly.
I didn't get as much done this weekend as I had hoped to, but I did get the main retract gear mounts made and fit. I made supports from 3/16 inch thick balsa and epoxied them to the sides of the nacelles where the main gear mount plates will reside. Next I cut the mount plates from 1/8-inch birch ply and fit the gear to them and marked the mount holes for drilling. I mounted the blind nuts and cut recesses to clear them in the balsa supports. I'll seal the wood beneath the mount plates with a thin coat of epoxy resin and then glue the mount plates in permanently tomorrow.
The following photos show today's work...
By the way, the holes in the back of the nacelles will be fitted with simulated turboprop exhaust pipes that will serve as air outlets. I think that will look neat! #^
Later - Bob Hunt
Personally I expect great things from your current effort.
It seems that everybody wants a Motorcycle License to allow them to buy a small and fuel efficient bike for commuting and for errands. That's actually a very bad reason to buy a bike...I sometimes consider buying a motorcycle for just that reason, then I reflect on the fact that I have totaled not one, but two bicycles by rear-ending cars and I change my mind.
I sometimes consider buying a motorcycle for just that reason, then I reflect on the fact that I have totaled not one, but two bicycles by rear-ending cars and I change my mind.You need to put a front brake on your bike ... and learn how to use it ;)
Derek, you could learn alot from Bob - those wheel pants came out of his workshop that way the same day the model was painted.
S?P
I'm thinking about offering a CD with all the construction photos that have been taken along the way on this project. There are lots and lots of them! Does anyone have any interest in this?
(snip)
I'd have to get enough interest in this in order to put the photos in chronilogical order and then have them burned to CDs. I'm guessing that the price on such a CD would be $5.00, plus shipping.
(snip)
Later - Bob
What's wrong with red, white, and blue? I'm a very patriotic kind of guy and those have become my new airplane colors. Everyone seemed to like the red, white, and blue on the Crossfire...
Nice Crist!Bob and Crist, ditto that on the Red, White and Blue. The new twin looks very cool.
It seems to me that now, more than ever before, we need to remember what the red, white, and blue stands for. I'm proud to have it on my plane. There may come a time when it is illegal to do this... Stranger things have happened recently...
Bob Hunt
What's wrong with red, white, and blue? I'm a very patriotic kind of guy and those have become my new airplane colors. Everyone seemed to like the red, white, and blue on the Crossfire... #^
Hey, at least it won't be bronze... n1
Add me to the Red White and Blue, crew too.
That's very nice, Chris. What plane is that at the right in the photo? Looks like either a Panther or a Cougar.
Bob Hunt
Maybe we need to paint the wing up like the flag, with bars and stars. I know its been done before.
That's very nice, Chris. What plane is that at the right in the photo? Looks like either a Panther or a Cougar.
Bob Hunt
Here's Bruce Hunt with a flag-ish scheme:
Right ; Well Then ; Where were we . R%%%%
Do you think Super Fil would be a good compound for making propeller molds? Does it smell as bad as bondo?
Thanks,
MM 8)
Bob, did you mask for your fillets? Just curious...
As long as you get it done before the Joe Nall. I want to see this plane fly!
Derek
P.S. I would like to take it for a spin too! ;)
PJ: Wait until you see the proof of concept twin we are building to ensure that the testbed will work... LL~
Marcus, when Bob told us that it was a test bed... i really thought that the blue stuff was not intended for moulding.... after that i almos saw some balls freeeeeeee but the soprano thing was the bestttttt
If everything goes as planned - and the weather cooperates - we will fly this monster later in the week. Pretty cold and wet outside right now... :-\
Later - Bob Hunt
Hi Crist:
You are in luck; the next twin (after the ones Buddy and I just started building...) will be a classic 35-size ship with two smaller motors and no retracts. The really neat thing is the world of new designs that has been opened by twins. We have a couple of really slick new ones drawn and lots more in the idea stage.
Later - Bob
This is a 'sport flyers' dream construction. As you know I will soon do something similar for my (Ahem >:D) RC designs.
If everything goes as planned - and the weather cooperates - we will fly this monster later in the week. Pretty cold and wet outside right now... :-\
Later - Bob Hunt
I blame Bob for the current Polar Vortex Snowpocalypse (TM) that's hit the Northeast.
I bet your foam supplier loves you> Great idea on the lining up the wing and fuse.
Hi Mark:knowing how hard you work on your finish,, Just thought I would pass it on,,
I'm not using the stock struts. I have had special ones made that are more robust. Also, I'm not using an actual E-Flite nose gear in the nose of this ship; it is a standard gear with no steering capability. I've researched these retracts quite a bit and am confident that they will perform well in this application. As a safeguard I might put "whisker skids" at all three gear points to protect the model in case of a malfunction. Of course these would only be used in practice; I'll remove them for appearance point judging and actual competition flights.
Thanks for your concern! H^^
Later - Bob
Aside from the minor issue with the servo wire fatigue,, ( not the strut wire) I think they are pretty darn reliable from what I have seen,,
You're absolutely right, Crist; I just threw the motors in place for the photos and I'll add the props and the spinners and check the CG before starting the drawings of the actual nacelles. I just had a few moments to take those last photos before having to go carve the bird for dinner... Some things take priority! <=
Later - Bob
Hi Wayne:
It is my understanding (please someone correct me if I'm mistaken...) that silicone emits a substance when it cures that will corrode wiring. Back when I was flying RC Pattern, I was told to never put any silicone anywhere near any electrical components.
I'd like to take this opportunity to say Happy Easter to everyone, to ask for God's blessings on us all, and to thank God for His gift of His Son, Jesus.
Bob Hunt
Hi Noel:
Actually a man I know that worked in the adhesive/chemical business told me to never use epoxy glue without a binding agent such as milled glass fibers or microballoons...
Later - Bob
Hmm, really? How about when laminating?
This is the third one, actually, isn't it? Whatever became of the first one and the test one? Or am I losing track? n~
I just thought that the building process of these ships might be of interest to the readers on this forum.
Later - Bob
Gee Wayne, it has dark gray on it now... LL~
Trust me, I'm working just about as fast as I'm able to.
Later - Bob
Great fit on the gear doors Bob. They are virtually invisible >:D
Primer goes on Sunday!
I think that electric planes have been around long enough that we don't need to have electron-themed names for the things.
Lesse -- twin engine, looks like a mosquito but it's not. Musquito, bug, interesting bug, interesting flying bug -- lightnin' bug!
Are you positive? Don't be negative.I ought to say something clever about staying grounded during these discussions ... but I won't.
I ought to say something clever about staying grounded during these discussions ... but I won't.
Dean
I think that electric planes have been around long enough that we don't need to have electron-themed names for the things.
Lesse -- twin engine, looks like a mosquito but it's not. Musquito, bug, interesting bug, interesting flying bug -- lightnin' bug!
F.R.E.D. shall rise again! H^^
Dean
Bob,
I am confused. What is the difference in the two twins. I know you had a test twin with profile nacelles. Are their two full bodied twins. Am I losing track of all your projects?
NOW we're talkin'!!! o2oP CLP** o2oP
I like how you went with a straight line over the top for rear portion of the "canopy", it looks more realistic than the Crossfire type. y1
The Crossfire canopy treatment is meant to simulate many of the modern jets that have such shaped canopies. The twin is supposed to be more of a private plane look. Although it's always madness on my part, there is often method associated with it. n~
Later - Bob Hunt
I spent Father's Day applying the red trim and a bit of the blue trim. Also got the canopy on. One more long day should do it!Bob,
Later - Bob Hunt
Thank you very much David. :)
Dan
Now, if I can just get out the slight hunt, I will be pretty happy with my new bird.
Here is a novel idea to at least try. One pusher and one tractor. I have no clue what it would do.
Future experiments include trying the props turning the other way. Right now the tops of the props are turning towards the canopy. We’ll try it with the tops of the props turning away from the canopy the next time out. This is a simple matter of switching any two wires on each motor and then switching the props and spinners. I guess, to cover all the bases, we should also try turning both props in the same direction just to be certain that we’ve left no stone unturned…
Plans may be a while yet...You using .014 solids or .018 cables ?
It has 650 square inches of area, but remember, I've quoted the battery on board weight. A glow twin with two .15 size engines would require 8 ounces of fuel (two four ounce tanks), and fuel weighs nominally an ounce per fluid ounce, so it's equivalent to a 60 ounce glow twin without that eight ounces. With the 20 inches of disk span, providing a lot of artificial air blast over the surfaces, and the greatly decreased drag with the retracts, it should do okay.
Later - Bob
Deuces are wild...here we see a pair of conspirators, double down on rudders (200% more than a Genesis mind you), and of course, Bubba flashing the international sign for twins...
I like the tail of the Turning Point and by chance would not retiring mean you'll be cutting cores for us to buy again? #^
Bet t looks even better in person. But, family and knees keep me home plus other stuff. D>K