Can I fit 2 Stroke .75 Engine in 40-50 size plane?

[blueberry]

Dear Guru,
Can I fit 2 Stroke .75 Engine in 40-50 size plane? It's a warbird. I'm having an extra JBA 2s .75 ABC engine ... with huge exhaust there ... Any advise on how to install and make safe of the installation for this case?

[AceViperX]

No problem.....
I have a 90 2stroke in a 46size aircraft. Guzzles fuel though.....

Installation should not be any different from the standard sized engine. Might have to get a exhaust manifold extender to clear the cowling though.

[nic]

it very much depend on the plane itself.

1) you may get a nose heavy plane,
2) a super fun plane
3) a plane than will not sit still on the ground when engine starts
4) or a plane that disintegrate in the air when you hit full throttle, because the structure is not design for such thrust/power.

but it is generally ok to put a slightly larger engine in a plane. But a 40LA (1.0hp) and a JBA .75 (2.1 hp) will give you very much difference in performance.

A tame plane may grow devil's horns with it.

[SniperWj]

not a pblm if you can get corrrect for ur plane after the 75 engine on it.

we like four stroke~ our ys110fz weight almost 700G on our 45 size warbird~

[blueberry]

Hey Guys,
These are marvelous info and experience sharing here... ok ... I'm very much in confident to start my new project now. Well bros, I trust you knew how it feels when a Warbird is %@$#!@$% by Sport Planes ... like M.Mustang... you know~

By the way, I was wondering if I can find the compatible Vertical Muffler for my JBA .75 2-stroke? Any advise?

[SniperWj]

btw~ big engine not mean can make ur mustang fast~

you got to look at the wing foil~ if very thick like cake then good for fly slow,not ezly to stall~

if you looking for fast mustang ~ then you got to choose a mustang with thin wing foil. small 40size 2stroke on a good thin wing foil can b very very fast.

me and my flying buddy just test a mustang with good thin wing foil with only os52 4stroke~last week~ very fast wor~~~no joke!

[blueberry]

Roger on that Capt. My sifu was flying Dago Red with OS 70 and the other was miss America (Mustang) OS70 also ... fast. (These two wait till I got my M.Mustang lar)

My new project will be Spitfire with .75 2-stroke. See can out run the .61 2 stroke Zero & 56alpha Warhawk?

I'm thinking to use prop 12x6 cos of 40 size plane. Can ar? or shall I use the 13x6 as per original recommended spec. But the problem is the dia" too big ... worry later taxi time the prop hit the floor. What you think?

[AceViperX]

Roger on that Capt. My sifu was flying Dago Red with OS 70 and the other was miss America (Mustang) OS70 also ... fast. (These two wait till I got my M.Mustang lar)

My new project will be Spitfire with .75 2-stroke. See can out run the .61 2 stroke Zero & 56alpha Warhawk?

I'm thinking to use prop 12x6 cos of 40 size plane. Can ar? or shall I use the 13x6 as per original recommended spec. But the problem is the dia" too big ... worry later taxi time the prop hit the floor. What you think?

The speed of the plane depends on the prop type used too. Instead of going from 12x6 t o13x6, go for a higher pitch prop like a 10x10.

[blueberry]

Bro,
This worries me. A 10 Dia' Prop wouldn't it be too small for such power full engine. My technical notes advised that under-size or over-size prop can damage the engine as the original load of the shafting and the rotating system is out of loading range. Can this be true? Of cos, seldom ppl will risk the piece of nice equipment with out-spec setup. Maybe you can share a bit on your actual experience.

[Dean]

Over Powering Setup

it very much depend on the plane itself.

1) you may get a nose heavy plane,
2) a super fun plane
3) a plane than will not sit still on the ground when engine starts
4) or a plane that disintegrate in the air when you hit full throttle, because the structure is not design for such thrust/power.

but it is generally ok to put a slightly larger engine in a plane. But a 40LA (1.0hp) and a JBA .75 (2.1 hp) will give you very much difference in performance.

A tame plane may grow devil's horns with it.

Bro Nic here is exactly right!
1. JBA .75 is 790gram with the muffler, "super head heavy". u will need 120 to 150gram at the back. Try moving rx batt right to the back of yr fuse(I meant near the rudder) this will help to avoid adding more weight.
2. It wont be super fun, it is SUPER FAST!
3. With a heavy setup, wing loading will be also super. U cann't fly slow.
Try a few diff Prop to see if it can idle properly, else super hot landing.
4. With 2.1 HP, it is advisable to reinforce the structure. I.e. around the fire wall area & MUST see if stabilizer strong enough for the "G". Full throttle Dog fight flying is a . & Divin full throttle is a . Throttle management will be sui sui.

have a feel of heavy setup here,
Maiden without full throttle yet.

http://www.youtube.com/watch?v=3rChYs85Kwk&feature=channel_page

Where do u guys fly? I'm flying with a group of hard core war bird siow PPFC.
Let's have a warbird FF meet.

Cheers Amigo

[blueberry]

OMG! That's fast ... the landing is killing. I hope the big wings I have from the Spitfire will help to compromise the thrust. My Zero is nose heavy as well ... I plane to add weight at the tail but sifu advise me that let it be nose heavy rather than adding more weight to the plane. We can trim the nose up in this case... to be honest, the plane is very diffc. to handle when she's at landing speed ... yao ar yao ..yao ar yao~~~

[nic]

I don't have any nitro warbirds, just 2 slow and easy nitro planes, but both are mildly over powered, (25fx on a .20 size plane, and 55ax on a 36-40 plane.). As both are old designs, based on older engine, the extra nose weight from these larger engines helps to move the CG in front. In fact, I still had to add a fair bit of nose weight on my .20 to balance it. Too much nose heavy is no fun to fly too. Just aim for CG where it is not tail heavy when your fuel tank is empty.

Keep your throttle in check when you fly. Keep your engine tune to the richer side (2-3 clicks maybe, depending on engine?), it prolongs the life of the engine and helps lower the rpm & hp.

Yes, wrong prop size will damage the engine, but what the manual states usually doesn't cover the full range that you can use. There are just too many combination of length X pitch readily available on the market to print on that tiny book.

[blueberry]

Right Nic. That's will be handy info. I have my Zero nose heavy at empty tank. For this Zero ... hai~ most of the manual cannot use ... except my Ki-61 Kyosho model ... the CG guide is perfect. At the end we still use the old method (Old Man Sytle) to determine it. It flies well now.

I agreed also to reinforce the original plane structure. Worry that the plane will break into pieces in the air.

I can imagine how my tamy Spitfire turns into wild beast with the.75 engine.

[AceViperX]

Bro,
This worries me. A 10 Dia' Prop wouldn't it be too small for such power full engine. My technical notes advised that under-size or over-size prop can damage the engine as the original load of the shafting and the rotating system is out of loading range. Can this be true? Of cos, seldom ppl will risk the piece of nice equipment with out-spec setup. Maybe you can share a bit on your actual experience.

Like what nic said, there are too many commbinations of prop size x pitch to list out but generally if u decrease the diameter by 1 and increase the pitch by 1 it should load up the engine just the same. Mind u this is only a rule of thumb and not always accurate so at the end of the day it's down to trial and error. But if it's speed you're after, then a higher pitch prop is what you're looking for.

Anyways unlike an eletric motor, a nitro engine is quite forgiving if you put on an unsuitable sized prop. Usually the only damage would be from overrevving the engine with a prop that is too small.

[blueberry]

Roger on that, Capt. You are all so helpful and knowledgeable. Thanks. I will come back again with my project development and the most important stage -- The Actual Flight ... Hope not getting a piece of KFC.

Anyway, have just lined up my Engine with the plane ... it seems nicely fit.

Here's a photo.