jpinegar

Hello,

I am considering putting a 90 size engine into a 40 size plane. I understand that I will have to counter balance the tail to ensure the weight and balance stays where it should but I am hoping for some advise. Has anyone done this before? Any thought and suggestions would greatly be appreciated. Thank you!!

mclina

Are you talking about a 90 four stroke or two stroke?

The other question that leaps to mind is, why?

More specifics on the plane/engine in question may help.

cruzomatic

My Feedback: (17)

Which plane are you talking about? Engine?

Alex7403

I don’t want to terminate your happiness too soon,
You will be able to balance it and it probably will take off, I just wonder if the wing will stay attached….

Alex

mclina

You will also need some very tall landing gear for prop clearance.

playntraffic

We run 75 and 90 sized engines on the Great Planes Easy Sport. You might need to run a higher pitch prop so that you get ground clearance. Tail draggers also work best because they point the nose in the air.

blvdbuzzard

What plane and engine is the question. The old Global .46 sized Ultimate flew very well on a .91 4s. Some 46 sized planes have Saito 82's, I am running a YS 63 in a 46 sized plane. I ran a Magnum .52 on the nose of a 40 Ugly Stick.

So, what plane and what engine?


Dru.

dignlivn

Hopefully your talking 90 size 4 stroke ?

I put a Saito 82 on a 40 size GP big stick
and I should have put in a larger fuel tank.
I ordered a 12 oz. to replace the 8 oz. tank.
It is slightly Nose heavy, I put 3 flights on her
just last week. Now I'm waiting for the bigger
tank. Good luck,


Bob

Mr67Stang

Cut at least 1 inch off the nose and move the firewall back. This will go a long ways towards helping you ballance the model. You may find that you will not like the results when you complete the project. Fact is you still have a 40 sized plane wing area and now you will increase the load on that wing which will deffinately effect the flight charactoristics. Some planes are more forgiving to the added weight than others. A Sig Kadet Sr. will accept a .90 a lot easier than a 40 size p-51 mustang for example.

hungryandbroke

If you're gonna go that much larger than whats called for you might as well try this one.....

http://www3.towerhobbies.com/cgi-bin...?&I=LXBY70&P=0

alfredbmor

I lost my GP Cap 232, .40 size this weekend because of a death stick. It solely does not mean much, what really means is the fact that I was using a Saito 1.00 in a .40 size plane. I had to put the nose down but the plane was pretty far from the runaway and in its last turn it stalled and was the end of it. This cap was a great performer but with the engine off it was a great brick. To conclude, yes I would put a .90 size engine in a .40 size plane but I would be more cautious checking the wing loading.
Good luck!!
Alfredo.

OzMo

My Feedback: (3)

I'll put it on my LT 40 if you send it to me

Jester241

My buddy has a Funtana .40 with an O.S. 91FX in it and it flies perfect. You'd never know it had a big motor in it. Of course it has unlimited vertical and stuff,but its also tame as my cat who is sitting right here on the arm of my chair as I type this. I say go for it! I'd recommend putting a lower pitch prop on as to increase thrust and decrease speed. It'll also let your plane slow more for landing which is a common problem with overpowered engines. And like the others said,watch your props ground clearence. Just dont fly it like its a racer,but rather more for 3D purposes and you'll likely find it'll be a good match. Just dont stress the airframe too much at high speeds. OH,and beef up the firewall and stuff too,and you'll likely have to shift some battery weight and stuff further back to balance.


Speaking of this topic,a club member at our field also had a .40 sized U-Can-do 3D plane with a .91 in also and it too flew great!

jpinegar

Thank you all for your advise. I was thinking about a 90 size two stroke in the somethin' extra - or simular airplane....I appreciate your help!!!

downunder

I'll go along completely with what Jester said. My son has an SC 1.08 in his beaten up 40 trainer and it flies beautifully. He shortened the nose by about 3" though to get the CG back where it belongs. It flies about as fast as it did with a much smaller engine but the prop pitch and lower revs of the large engine hold the speed down so there's no risk of ripping wings off. There's very little difference in all up weight so stall speeds are much the same as before. In fact I worked out that if it stalled at 20mph with a 40 then it'd now stall at 22mph which is too small a difference to notice. With a 16" prop though and the standard undercarriage it has to take off and land with the tail wheel on the ground.

hungryandbroke

Even though my sig somethin' extra flew very well with an OS 46AX, you will notice a huge difference by going with a 91 2-stroke on that plane......difference is......it'll suck up a LOT more fuel!

My goldberg tiger 60 with a super tigre G-90 on it has me one step away from the poor house it sucks up fuel so fast! []

I might consider a 61 at the most on the somethin' extra, but never a 91!

Fastsky

You might have another problem. With the larger prop on the plane it might not want to come down. I put an OS32 which isn't that much bigger than a 25 engine on an LT25 trainer and at idle the plane would slowly cruise along without losing altitude!!

Allfat

My Feedback: (1)

I watched my buddy maiden his Something Extra yesterday with an OS 55AX on it and it was more than enough engine for that airframe. It could do whatever he wanted it to do and landings were no problem.

pcofield

I am a big fan of over powering myself but there are concerns. I have a 35 size mid wing sport plane with a st 90 2c engine I only ran this engine for the sake of speed . The plane is so over built strength is not an issue.Landings are pretty hot needing power simply to maintain level flight.I have a twist 60 with a crrc26 gasoline engine on it. This plane flies fantastic but there is a slight change in low speed handeling. Worth the sacrafice with this air frame.Before you over kill on your plane you need to weigh out fuel consumption weight and your flying style/flying skill. Most planes I am willing to go twice over the recommended however on a 40 size sukoi with a magnum 91 4c you will fold the wing. I know I did

leepord geko

This plane is a slow flyer plus aka not meant to go fast, youll never get the ground clearence because there right in gas problems too where your going to need a 12 oz tank that won't fit and just put in a 55ax. Another thing is vibration because its a very delicate plane.

Charlie P.

You can add the .90, add beefier landing gear, reenforce the firewall, and lots of tail weight - and then you get a model that flies like a .90 with excessive wing loading. Yea.

Get a .40 size Quickie 500 and put a .40 in it - it will fly better, because lighter flies better, and most likely faster.

Cyclic Hardover

My Feedback: (3)

Been there "do that." My entire fleet is overpowered. Set up right, can fly just fine. Go check the My Models. Shoot, I have a Saito100 on a 40 P-51

ErikElvis

My Feedback: (2)

I had a OS 91 surpass in my 40 size (well I think they label it as a 50 size) sundowner 50. And it didnt require much Tail weight when the largest engine it calls for is a 82 4 stroke. It dead sticked in HOT. It dropped fast but responded well to the elevator for the flair.

GRANT ED

I had a .91 four stroke in my .46 size UCD 3D. As is turns out it was a mistake. It made the plane not very nice to fly. Almost always below 1/2 throttle. Could do awesome vertical climbs but big whoop. That thrill wore off quickly. I had to shut the motor off to land as the residual thrust at idle was enough it would float forever. Also the heavier .91 made the wing loading higher than it should have been. If I had my time again I would have used a .7 or .8 engine. People will tell you that you can't overpower a model. They are wrong.

Stripes

My Feedback: (19)

I put a pumped 120 Surpass II into a Dirty Birdy and it flew very nicely. Finally I had an airplane that wasn't underpowered.