Total Displacement

If one were to build a multi-engine stunter (4+), what would be the the total engine displacement allowed? Whats the formula to figure whats the max that could be used?

Thanks,

Under AMA or FAI rules it would be the total displacement allowed divided by the number of motors used= the displacement per motor.

Jake

Hi

Once (many years ago) I did a colaboration of a C/L twin but could not get both motors running the same. Got one to peak and the other would die. It still flew but never got both engines to peak at the same time. Thought it was a harmonic vibration thing upsetting the other motor.

Anyone know what was happening and how to fix it.

Well, I used to think I knew, but now I'm pretty sure I don't.

You can run 4 18s or 4 15s would be easier to find

>If one were to build a multi-engine stunter (4+), what would
>be the the total engine displacement allowed? Whats the
>formula to figure whats the max that could be used?
>
>Thanks,
>
>Kirk

It is simple additon. I think AMA rules allow .70 max with multi 2-stroke engines. You could thus use two .35 engines under the current rules, but could not use a .70 cubic inch single 2-stroke motor. That should all change, however, in 2005 for both AMA and FAI. Let's see, anyone want to build a B-36 with six .20s?

I understand you are a pilot as well as wingwalker with many years of experience and a long history in aviation. An interesting question!
However, a reliable single engine stunter that performs without midflight adjustment with adequate power to weight ratio and trim for several given conditions in the manner most reliable is certainly quest enough for all but a few among us. The most successful and his pit crew worked their butts off.

I always think of Gordy and his early and later twin engine experience. Good fodder around the pool after hours at the Roadway in Tuscon. Jack Sheeks has some multi-engine stunter experience. Windy, Paul Walker, and a really nice guy from the North West. He won the I- Beamer award again this year I think. An east coaster with a good flying Half/A profile and several Mosquito semi scale builders to include Steve DeJulia. Frank McMillan also did the semi scale twin thing I believe.

Dan Banjock has British a WWI single engine, single seat, mid engine pusher, with an OS 40FP (I think?) and a custom shaft extension that works. No flaps and very nearly scale presentation that will perform the whole pattern in bad air pretty well. I dont remember the nomenclature.

LAST EDITED ON Apr-01-04 AT 04:21 PM (CDT)
 
John,

Yes I am a pilot and fly air shows. I have wing walked 4 times but I decided years ago to fly the plane rather than walk on it. Though I have a 450 Stearman now for wingwalking, my true love is hard core acro. My first plane was Pitts S1-S that I bought 3 months after getting my ticket. I then bought a Clip wing T-craft that had about the same performance as a Pitts S2-A (a real fun sleeper plane!). I then bought the only (at the time) CAP-21 in the country. Now there are two. They only ever made 17 and there are 13 left now. It had .2 hrs on it and looked and flew amazing. I now have the 450 Stearman for wingwalking. I am also lucky to have a wide range of acro planes to use from Extas, Pitts, Sukhoi, etc. I start my Jet training in the Fouga as soon as the weather clears up here. Besides flying acro I am an A.C.E. for Aerobatic sign offs to fly acro below 1500 feet. Been doing shows since 1986 and now get to fly with all my heros from my early years.

Now knowing all this, Don't want to get your ole Chevelle SS out of my hands!!!!

Kirk www.wingwalk.com

PS. I have the Chevelle ready to go and maybe this weekend or next it will be in the air again. Last chance to save it! It will be well cared for!

WHEW...
When do you rest?
Stearman huh? Always loved that airplane- even if only from afar...

Jake

Jake,

I guess you could say I am resting now by building and flying control line with my two son's. They are older (6 & 8) and in school now which make doing the air shows a logistic nightmare. You know, baby sitters, missing school, and worrying about them running off with the car while dads away. Besides, they would kill me if they found out I was at an air show and didn't take them!

No, I would rather spend the time with them at this stage in the game and go back to do shows later. Ben my eight year old is now flying solo flights from takeoff to landing on the Streak Trainer. The Six year old Patrick (Named after his God Mother Patty Wagstaff) is almost ready to solo. They both fly the Stearman whenever I can get them in the air. You could say I'm a proud daddy and want to share my love of aviation with them but not force it on them. So if they don't take to it you won't have to watch from a far. I'll take you in as my long lost son and you can sit in the front row!

Let's rock.
E-mail me at your convenience, I have a little story or two to share with you.

Thanks!

Jake

[email protected]

>John,
>
>Yes I am a pilot and fly air shows. I have wing walked 4
>times but I decided years ago to fly the plane rather than
>walk on it. Though I have a 450 Stearman now for
>wingwalking, my true love is hard core acro. My first plane
>was Pitts S1-S that I bought 3 months after getting my
>ticket. I then bought a Clip wing T-craft that had about the
>same performance as a Pitts S2-A (a real fun sleeper
>plane!). I then bought the only (at the time) CAP-21 in the
>country. Now there are two. They only ever made 17 and there
>are 13 left now. It had .2 hrs on it and looked and flew
>amazing. I now have the 450 Stearman for wingwalking. I am
>also lucky to have a wide range of acro planes to use from
>Extas, Pitts, Sukhoi, etc. I start my Jet training in the
>Fouga as soon as the weather clears up here. Besides flying
>acro I am an A.C.E. for Aerobatic sign offs to fly acro
>below 1500 feet. Been doing shows since 1986 and now get to
>fly with all my heros from my early years.
>
>Now knowing all this, Don't want to get your ole Chevelle SS
>out of my hands!!!!
>
>
>Kirk www.wingwalk.com
>
>PS. I have the Chevelle ready to go and maybe this weekend
>or next it will be in the air again. Last chance to save it!
> It will be well cared for!

No, Thanks Kirk but if I can get an acrobatic ride from you some day I will trade what I info I have about making that particular Chevelle fly better!!

LAST EDITED ON Apr-01-04 AT 00:15 AM (CDT)
 
>>If one were to build a multi-engine stunter (4+), what would
>>be the the total engine displacement allowed? Whats the
>>formula to figure whats the max that could be used?
>>
>>Thanks,
>>
>>Kirk
>
>It is simple additon. I think AMA rules allow .70 max with
>multi 2-stroke engines. You could thus use two .35 engines
>under the current rules, but could not use a .70 cubic inch
>single 2-stroke motor. That should all change, however, in
>2005 for both AMA and FAI. Let's see, anyone want to build
>a B-36 with six .20s?

This can currently still be modified by 60% rule for 4 strokes, allowing a total of 1.16 cu. in. (apparently) for multis (60% x 1.16 =.696 cu. in.). Apparently this whole load would go away in '05, or '06, when we adopt the 1.2 cu.in. rule from FAI.

Also, I don't understand Randy's math...four x .18 = .72, or .02 over the multi engine limit. The other thing to consider is that most engine displacements are really approximations. The R/C industry generally doesn't give a rat's posterior how big an engine is, so they just make theirs "a little bigger" for perceived marketing benefits. Steve

How about a .40 in the nose and two .15s on the wings?

>How about a .40 in the nose and two .15s on the wings?
>
>

Or two .20s in tandem on the fuselage? (push, pull). Then two .15s on the wings. Make it exciting for when you want to get this thing started. Hmm, better use a stooge. I don't know if I want to launch that.

"""""Also, I don't understand Randy's math...four x .18 = .72, or .02 over the multi engine limit. The other thing to consider is that most engine displacements are really approximations. The R/C industry generally doesn't give a rat's posterior how big an engine is, so they just make theirs "a little bigger" for perceived marketing benefits.

Steve """"""

Hi Steve

Let me explain my math, The AMA rule in multi engines is a 72 displacement. It is not 70
You can use 2 - 36 engines, or 4 - 18s this would push the limit.

or , you can use 4- 15s which would only be 60.
or If you wanted you could use 6 12s

there are many combinations you can go with, please see the enclosed graph, I think it will explain this

Regards

Randy did the math correctly.....the single engine limit in our AMA is .65 CID, while "multiple" engines are allowed .72 CID.

As I understand it, future FAI regs will allow the the new Benz V-12.

See Ya

OR..... If you like you could build a plane with 7 of the new magnum 10 CL engines ,
3 on each wing and one in the nose!
That would be a site. Maybe have to PAY Howard to help crank em all for you though.

You are close Randy but are one motor short for one of the project planes. The plane on the front burner has Twelve! This was a topic of conversation and I am not the one wanting to build this. Now let's see who can figure out what plane/planes we are talking about here?

Don't tell me you are going to build a Dornier "Do-X" flying boat? I would love to see that fly the pattern.

ding ding ding!!!! And the winner is Bill. Yep a buddy and I were talking about something different and quite frankly...OFF THE WALL.

That was about as off the wall for stunt as we could come up with at the time. "Need more Beer" (Homer Simpson) Yes this was just a topic we were banting about and that's when the question of total engine displacement came up. Don't expect to see me building this one! Maybe Dan Banjok could do it. I saw a cool video of his WW1 pusher doing the pattern. Sorry Dan if I murdered your name but I think people know who I'm talking about.

Apparently this whole
>load would go away in '05, or '06, when we adopt the
>1.2 cu.in. rule from FAI.
>
>http://www.nwskyraiders.com/index.html

Actually, the new limit proposed for the FAI rules is 15cc which translate to about 0.92 cu in.

This is the proposed new limit for the AMA rules as well.