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Author Topic: Formula 40  (Read 3809 times)

Offline Motorman

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Formula 40
« on: April 27, 2020, 02:55:06 PM »
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« Last Edit: August 22, 2021, 12:04:47 PM by Motorman »

Offline kenny B

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Re: Formula 40
« Reply #1 on: April 27, 2020, 04:38:30 PM »
if you want one that works every time, build "The Move" Mike Hazel.

Offline Carl Cisneros

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Re: Formula 40
« Reply #2 on: April 27, 2020, 11:08:29 PM »
Taint just the plane but the entire combo and set up to be fast.

Carl

Carl R Cisneros, Dist IV
Control Line RB

Offline Carl Cisneros

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Re: Formula 40
« Reply #3 on: April 28, 2020, 08:14:03 AM »
Carl R Cisneros, Dist IV
Control Line RB

Offline Mike Hazel

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Re: Formula 40
« Reply #4 on: April 28, 2020, 09:38:47 AM »
Then try Bill W's Pink Lady F40, and plan on running the engine clockwise unless you already fly that direction. Plans and article in Model Aviation magazine, circa 1987.

Offline bob whitney

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Re: Formula 40
« Reply #5 on: April 28, 2020, 11:13:42 AM »
what Mike said
rad racer

Offline bob whitney

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Re: Formula 40
« Reply #6 on: April 28, 2020, 07:24:39 PM »
 build it up rite  and save your self a lot of grief
rad racer

Offline Peter Lott

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Re: Formula 40
« Reply #7 on: April 29, 2020, 12:01:30 AM »
If you're flying anticlockwise with a right-hand rotation engine and an inverted engine, too many dynamics causing the aircraft to roll and turn into the circle.

Which raises the next point... I'm building a Pink Lady F40 for a Rossi .40 (unusual choice I know) but this Rossi has a left-hand crankshaft. More problems, where to get a left-hand prop in the 8x8 size region... ;)

Offline bill bischoff

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Re: Formula 40
« Reply #8 on: April 29, 2020, 06:49:13 AM »
Eliminator Props has a 7 1/2 x 7 3/4 LH Form. 40 prop for sale.

Offline Peter Lott

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Re: Formula 40
« Reply #9 on: April 29, 2020, 06:55:32 AM »
The torque of the more conventional right hand rotation engine will roll the airframe to the left, into the circle of an anticlockwise-flying model.
The swirl of the airflow off the propeller of a more conventional right hand rotation engine impinges on the outboard side of the inverted engine cowl, turning the aeroplane into the circle of an anticlockwise flying model.
If the fin is a conventional top/dorsal fin, this same swirling airflow impinges on the left hand side of the fin, pushing the tail right (and the nose into the circle of an anticlockwise flying model).
The P-factor causes inward thrust (nose left) turning the aircraft into the circle. P-factor is where the aircraft rotates nose-up for takeoff, the down-going propeller blade angle of attack increases and creates more thrust.

Offline bob whitney

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Re: Formula 40
« Reply #10 on: April 29, 2020, 10:26:07 AM »
I think the problem is the newer engines turning so many RPM;s.with the old K&B's and the ST;s 18,000 was a lot of RPM .now we are turning 24,000 to 28,000 with no problem, with more torque
rad racer

Offline Peter Lott

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Re: Formula 40
« Reply #11 on: April 29, 2020, 10:45:32 AM »
Very likely Bob, I guess that’s where the Nelsons are turning

Offline bill bischoff

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Re: Formula 40
« Reply #12 on: April 29, 2020, 02:25:29 PM »
Actually, P-Factor has to do with the angle of attack of the relative wind to the prop. Consider a normal, CCW flying airplane with a normal CCW engine. At rest, the outboard blade is sitting at a higher angle than the inboard blade since the model is sitting nose high. On launch, the higher angle of attack of the outboard blade creates more thrust than the inboard blade, causing a yaw into the circle. Gyroscopic precession is a different issue. So, yes, P-Factor IS about thrust.
« Last Edit: April 29, 2020, 08:33:34 PM by bill bischoff »

Offline BillLee

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Re: Formula 40
« Reply #13 on: April 29, 2020, 03:39:37 PM »
Actually, P-Factor has to do with the angle of attack of the relative wind to the prop. Consider a normal, CCW flying airplane with a normal CCW engine. At rest, the outboard blade is sitting at a higher angle than the inboard blade since the model is sitting nose high. On launch, the incoming air is parallel to the ground, not the crankshaft axis, The higher angle of attack of the outboard blade creates more thrust than the inboard blade, causing a yaw into the circle. Gyroscopic precession is a different issue. So, yes, P-Factor IS about thrust.

Well, I'm no pilot, but it seems to me that your statement "On launch, the incoming air is parallel to the ground, not the crankshaft axis" is ignoring the in-flow of air. Certainly at launch, the model is at zero velocity relative to the ground, but there most certainly is air moving, and it is moving parallel to the crankshaft. Yes, as the model accelerates, the "parallel to the crankshaft" changes, but then, so does the angle the crankshaft makes relative to the ground.

IMHO, P-factor is much-a-do-about-....very little.
Bill Lee
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Offline bill bischoff

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Re: Formula 40
« Reply #14 on: April 29, 2020, 08:32:35 PM »
OK, semantics. How 'bout the above revision?

Offline BillLee

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Re: Formula 40
« Reply #15 on: April 30, 2020, 07:13:27 AM »
OK, semantics. How 'bout the above revision?
And, of course, why some very successful models are made with a  ground attitude that is very close to level and a sub rudder to address the spiral outflow.

Has anybody ever quantized the relative importance of the various forces? Is P-factor important? Is relative torque important? How about the spiral flow?

Seems like a side-winder with short gear and sub rudder would be advantageous. I.e., near zero AOA on the ground, spiral flow pushing the nose down and the tail in, lateral CG outboard of the thrust line, smaller frontal area, ....

I suspect that the engine torque is the biggest problem, Anybody have direct experience?
Bill Lee
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Offline Peter Lott

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Re: Formula 40
« Reply #16 on: April 30, 2020, 08:19:03 AM »
Eliminator Props has a 7 1/2 x 7 3/4 LH Form. 40 prop for sale.

Thanks for the pointer Bill! I'm on it... :)

Offline bob whitney

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Re: Formula 40
« Reply #17 on: April 30, 2020, 06:32:14 PM »
And, of course, why some very successful models are made with a  ground attitude that is very close to level and a sub rudder to address the spiral outflow.

Has anybody ever quantized the relative importance of the various forces? Is P-factor important? Is relative torque important? How about the spiral flow?

Seems like a side-winder with short gear and sub rudder would be advantageous. I.e., near zero AOA on the ground, spiral flow pushing the nose down and the tail in, lateral CG outboard of the thrust line, smaller frontal area, ....

I suspect that the engine torque is the biggest problem, Anybody have direct experience?

yes  S?P
rad racer

Offline bob whitney

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Re: Formula 40
« Reply #18 on: April 30, 2020, 08:11:30 PM »
being an old Fart I was flying the old B proto then f 40 and then 21 proto

the old inverted  B proto's never had a problem coming in  when the newer schnurlly (spelling) engines came out the inverted ships started going away. it didn't take long for the F 40 guys to learn the only way to safely fly inverted was with a left hand crank .the only two I remember doing well were Bill Wisniewski add Jim Rhoades. for a couple of years I flew F 40;s at the nats for Frank Garzon and his N.Y. guys .they were all uprite and u could take off in the pylon if u wanted to.

when 21 proto started there were 4 inverts Barry Tippitt Wayne Trivin ,Chris Sackitt.and myself.most others were uprite.Chris,wayne and Barry had Rossi's and all had problems on take off..on about every 3rd or fourth flight waynes would come in and flip over .had to fly it like an F2C on take off.one time it came across the circle and when it hit the lines on the other side it snapped my shoulder and it has never been the same ,doc says it was a Tommy John thing/.

mine has a custom OPS with a Rossi crank .it didn't have the torque of the Rossi but turned more RPM's I used an F2C prop .3 years in a row I placed 2nd to Glenn Lee's uprite. then it crashed for some un known reason (more on that later)

my next ship was still inverted but with a Rossi.now mine was doing the same thing as the other 3.i had to add more tip weight ,move the leadouts back and go to a smaller prop ,dropping about 3 MPH then it was flyable. I have flown Glenn's uprite and it is A joy to fly'

3 of the ships I have been talking about crashed the same way.Rhoades and Trivin's F-40's and my first 21 proto. all three were were flying level .a little down was given and all 3 went in like the up line had broken.nothing could be found wrong with the controls on any of them

the 40 size inverted Rats never seemed to have these problems but I noticed that they have much bigger Stabs and maybe the smaller F-40 and 21 Proto stabs are loosing lift because of the cowl on the under side

as a side note ,originally Sub Rudders were not aloud on 21 protos .today all F-40's and 21 proto's have sub rudder's

I know this is long, I hope it makes some sense .Rad the OLD MSN H^^
« Last Edit: May 01, 2020, 08:52:15 AM by bob whitney »
rad racer

Offline Bob Heywood

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Re: Formula 40
« Reply #19 on: May 02, 2020, 07:01:34 AM »
Why has no one mentioned the center of mass effect of the lines at initial acceleration (F=Ma) dragging the plane into the circle?

The obvious solution is to fly CW.
"Clockwise Forever..."

Offline BillLee

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Re: Formula 40
« Reply #20 on: May 02, 2020, 10:30:57 AM »
Why has no one mentioned the center of mass effect of the lines at initial acceleration (F=Ma) dragging the plane into the circle?

The obvious solution is to fly CW.
Bob, your premise (center of mass effect of the lines at initial acceleration) does not lead to your conclusion (fly CW).

Line mass dragging into the center will be the same in either flight direction.

Direction of flight helps/hurts take-off reaction as a function of engine rotation direction. I.e., fly CW with a "normal" rotation engine to get torque reaction to roll the model out, or fly CCW with a reverse rotation engine.
Bill Lee
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Offline Bob Heywood

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Re: Formula 40
« Reply #21 on: May 02, 2020, 10:49:37 AM »
Bob, your premise (center of mass effect of the lines at initial acceleration) does not lead to your conclusion (fly CW).

Line mass dragging into the center will be the same in either flight direction.

Direction of flight helps/hurts take-off reaction as a function of engine rotation direction. I.e., fly CW with a "normal" rotation engine to get torque reaction to roll the model out, or fly CCW with a reverse rotation engine.

I know. I just had to say it. Harry Roe, Jerry Roselle, and Jack Frye all believed implicitly that CW was the only proper way to fly C/L Speed. These guys were my mentors. I'm a hard core disciple.

The mass reaction is real. That's why tip ballast is used. When flying CCW with a right hand turning engine everything conspires to work against you. When flying CW you get some help. I do concede that an F40 with a modern engine accelerates violently and pushes everything to the limit.
"Clockwise Forever..."

Offline Bob Heywood

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Re: Formula 40
« Reply #22 on: May 04, 2020, 06:04:08 AM »
....
"Clockwise Forever..."

Offline C.T. Schaefer

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Re: Formula 40
« Reply #23 on: May 05, 2020, 04:45:43 AM »
That looks like me when I built an asymmetrical uprite 40 ship. It chased me a couple of times and flew crappy when it did get in the air.  Sawed out the wing and re-booted with normal wing. Fine after that!   TS

Offline Les Akre

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Re: Formula 40
« Reply #24 on: May 06, 2020, 12:53:08 AM »
Myself, I always had problems with Inverted F-40's. Around 2002 or so, I built the first of three modified versions of Jim Rhoades Airplane which was an Upright with a sub rudder and never looked back. Ground handling was far superior on takeoffs than the inverted models. There was much speculation as to why, but AFAIWC I didn't care...It worked. The .40 Rats worked out better inverted because they usually had more wing length and stab area and also weighed more.
There was a guy named Fred Anderson from Calif. that built a sidewinder F-40. I can't remember if he completely finished the model and flew it though.
Pics of his model are below.

Les

Offline Les Akre

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Re: Formula 40
« Reply #25 on: May 06, 2020, 12:56:16 AM »
Another pic

Offline Les Akre

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Re: Formula 40
« Reply #26 on: May 06, 2020, 12:57:50 AM »
And Another

Offline Les Akre

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Re: Formula 40
« Reply #27 on: May 06, 2020, 12:59:11 AM »
Again...

Offline Les Akre

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Re: Formula 40
« Reply #28 on: May 06, 2020, 01:00:07 AM »
Last one

Offline Jim Rhoades

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Re: Formula 40
« Reply #29 on: May 28, 2020, 09:45:26 PM »
     My name has been mentioned several times on this subject so I'd like to put in my two cents worth.  I flew quite a few different F40's of all different configurations all flying clockwise as I fly stunt as well as speed.  Starting with John Boles's OS 40 VRP powered Pink Lady.  It was a real handfull on takeoff needing lots of running room on launch.  No chance of hanging on to the pylon with the other hand on launch.  Placed 4th I think at Reno Nats.  I acquired Bill Nusz's Nelson 40 FIRE F40which was one of the early upright cowl bottom rudder ships and it was an absolute dream  to take off.  No tendency to come in on take off.  Once it ws  launched in on me and it just dropped the inboard wing and went straight dragging the lines about 40 ft then took off normally.  Bill was one of the first to recognize the effect that the spiraling prop wash had and how the upright cowl and bottom rudder kept the model out on the lines on takeoff without tip weight.  I flew Bob Spahr's sidewinder asymmetrical F40 probably a half dozen times.  Wow!  Start at least 10 ft from the pylon and run like hell.  Lines were never tight for almost 1/3 lap!  Tip weight was all on the inboard side along with the line weight.  Not the way to build a F40.  Marty Schoenheiter built an inverted engine F40 with a bottom rudder that I was also the pilot for.  The aluminum landing gear bolted  to the head with a rather wide strut to a wheel cover.  All that forward bottom area with the spiral prop wash caused a turn in on the first takeoff which took out the wheel cover.  Several oz of tip weight made it possible to fly with plenty of running room on takeoff.  His next model was an upright engine bottom rudder ship which flew fine.
     The moral of the story is that the Pink Lady with its short landing gear is probably the cleanest aerodynamically and works well when flown clockwise like Willy's did, or counterclockwise with left hand props.  For the rest of us that fly counter-clockwise the upright cowl bottom rudder is the way to go.  They don't even need tip weight which is a plus as F40 is an acceleration event as well as top speed.  By the way I held the F40 record for 9 years from 1998 with the Nusz model until bettered by the current holder.

Jim Rhoades

 PS.  I can furnish a full scale 3 view of the Nusz model if needed.  Send email of PM.

Offline Jim Rhoades

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Re: Formula 40
« Reply #30 on: June 02, 2020, 11:48:56 PM »
Motorman,

     Props you sent?   I know nothing.  Not sure who you sent props to but I was not made aware of it at all.
     I don't recall just when I lost my F40 ship but it was at one of the first NW Regionals held in Roseburg OR.  I had loaned out my handle and lines and the neutral was adjusted and I had forgot about it.  I had actually retired the ship as I only had 3 bolts actually holding the engine and one was into a helicoil.  I decided to take it to the Regionals for one last flight.  I usually only flew only one flight and  the needle valve had not needed adjusting for well over a dozen flights.  The model was started and launched and after 1/4 lap hugging the ground I got the model in the air with all the up I could give on the handle but the model was only less than a foot off the ground.  The slight ground slope on the circle was met with a small bounce followed with a bigger one next lap.  The next one bent the titanium gear enough to shorten the prop a bit over an inch and stop the engine but the model was destroyed.  That titanium landing gear had been deflected a full inch but had sprung back to its original shape.  Good stuff!  The end of my own F40's as its replacement sits with only a couple half completed parts.   My bad.

Jim Rhoades


Offline Tim Wescott

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Re: Formula 40
« Reply #31 on: June 03, 2020, 09:06:16 AM »
... all flying clockwise as I fly stunt as well as speed....

I don't remember you flying backward - do you mean aunty clockwise?  (I.e., "Cox", not "Resinger").

... schnurlly (spelling) engines ...

Schnuerle, or if you want to be hoity-toity, Schnürle.  Doubly weird (to us in the US) because it's German and because it's some guy's name (Adolph Schnürle).
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Mike Hazel

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Re: Formula 40
« Reply #32 on: June 03, 2020, 12:50:15 PM »
Jim,   You have several weeks before the NW Regionals, get that F40 finished!  I will give you a prop if you can do it!  My "Kortness F40" copy  is a good one!  Did a 158 flight with it, I was hanging on.... wahoo!!!!  ZZ

Offline Jim Rhoades

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Re: Formula 40
« Reply #33 on: June 04, 2020, 06:12:55 PM »
Mike,

     I've been thinking a bit about doing just that.  I have pretty well everything I need to build it but I really think that I can make a wing lighter than the one I have started.  It is a balsa wing with basswood stub spar that is more than needed if some carbon is put to use.  I think I can make another that is less than 2/3rds the weight using carbon reinforcements and less basswood.  More time consuming work.  The model was to be the same as my Nusz ship with a new twist in the form of an inverted V tail.  Stab and bottom fin all in one package.  The stab is built with carbon rod leading edges and titanium tips.  Just needs unidirectional carbon vacuum bagged to stiffen it.  The center dihedral joint is re-enforced with kevlar.  The fuselage will have a basswood crutch with the rest being balsa with carbon re-enforcing.  Engines are ready to go and a new lighter fuel tank needs to be made.  The landing gear can be salvaged from the old ship.
     Then I need to et a ROUND TUIT!

Jim Rhoades


Offline Mike Hazel

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Re: Formula 40
« Reply #34 on: June 04, 2020, 07:32:14 PM »
Those "Round Tuits" are sometimes hard to come by. 

Offline John Moll

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Re: Formula 40
« Reply #35 on: June 27, 2020, 07:07:49 PM »
CW or CCW, Just whip the CRAP out of it on takeoff and get into the pylon ASAP!!! If you don't whip it you better run like hell

Offline PaulGibeault

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Re: Formula 40
« Reply #36 on: October 19, 2020, 03:56:13 PM »
Mike,

     I've been thinking a bit about doing just that.  I have pretty well everything I need to build it but I really think that I can make a wing lighter than the one I have started.  It is a balsa wing with basswood stub spar that is more than needed if some carbon is put to use.  I think I can make another that is less than 2/3rds the weight using carbon reinforcements and less basswood.  More time consuming work.  The model was to be the same as my Nusz ship with a new twist in the form of an inverted V tail.  Stab and bottom fin all in one package.  The stab is built with carbon rod leading edges and titanium tips.  Just needs unidirectional carbon vacuum bagged to stiffen it.  The center dihedral joint is re-enforced with kevlar.  The fuselage will have a basswood crutch with the rest being balsa with carbon re-enforcing.  Engines are ready to go and a new lighter fuel tank needs to be made.  The landing gear can be salvaged from the old ship.
     Then I need to et a ROUND TUIT!

Jim Rhoades

Jim Rhoades is really the most consistently high performing F-40 flier I've ever seen. This is why I use his plan and after some effort getting the other details right, I'm at the level Jim left some 10 years ago!  Form 40's have evolved to this planform much the same way FAI speed models are head outboard asymmetrics. It's high speed takeoff is the easiest to fly & it doesn't give the pilot the willies on takeoff. Once airborne it's the easiest (most STABLE) layout for the average pilot to fly low to the ground. The inverted Wisniewski type layout ONLY works properly when flown CW. (OR possibly CCW using a left hand prop).  I believe ultimately the inverted model may be aerodynamically faster, but the vast majority of us fly CCW and accept the rather small compromise. My current model built the old fashioned way is based on Jim's plan with my own (deficient) modifications rendering it nose heavy. There's no plan since I'd rather not offer a plan with known built in errors.
Shown is my latest model with (N-40 FIRE)  "for go" & flies at 159-161 MPH.
A lighter weight composite built model will be the next breakthrough, IF there remains anybody left interested in flying this event. The current 164 MPH record set by Dave Mark has stood for quite a looong time...

Offline PaulGibeault

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Re: Formula 40
« Reply #37 on: October 19, 2020, 04:00:54 PM »
This is an original 150+ MPH Mike Hazel designed Move with Nelson 40 RIRE engine. Excellent model although it's built over strong like a rat racer & heavily painted, therefore on the heavy side for ultimate competition. It has survived for over 25 years though!


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