GP Ultimate Bipe .40 + Saito .91?
 

I know, I know, why does everyone have to overpower their planes so much???? I just want to know if this is too much engine for this plane. I have the .91 that my wife bought me for my birthday, but just no plane to put it into. Honest opinions here guys, whatcha think?

GP Ultimate Bipe .40 + Saito .91?
 

BK:

Sad to say, the .91 is a hard size to find a good plane for. It's too big and heavy for the .40 planes, and not powerful enough for the 60s.

That having been said, the Ultimate .40 would probably be as good as any. You might want to watch the projected weight and balance as you build, possibly want to knock an inch or so off the nose.

Bill.

GP Ultimate Bipe .40 + Saito .91?
 

The Saito 91 is only an ounce or two heavier than most of the .46's on the market today. I have seen one in a GP Ultimate bipe and it flew the plane very well. The plane can handle this engine just fine (the Saito 91 is lighter than the Saito 65).

Cheers!

Jollidude

GP Ultimate Bipe .40 + Saito .91?
 

Bill, thanks for the information. Actually, unfortunately the plane is already built with an OS 46fx in it, I was just trying to figure out a plane for it to go into without having to buy a new one (you know how we all hate to do that :D ). I might go ahead and see how that thing will do in there. I've been dying to get that plane back in the air.

Jollidude, thanks for the info. Didn't realize they were so close in weight.

GP Ultimate Bipe .40 + Saito .91?
 

I am also planning on putting a Saito .91 in a GP Ultimate. With a 14x6 prop the ground clearance is marginal, but hopefully doable. . I don't like going to a three bladed set up due to additional costs and reduced performance. Just another thought.

GP Ultimate Bipe .40 + Saito .91?
 

BK:

With Jolly's weight info at hand, it sounds like you could just about strap the Saito on and go flying without any other bothers.

Bill.

GP Ultimate Bipe .40 + Saito .91?
 

I would definitely watch the prop clearance. The one bad feature about this plane is the the landing gear tend to flatten out on landings.

GP Ultimate Bipe .40 + Saito .91?
 

Would this engine cause a problem with landing as far as it not idling down low enough to lose enough speed? Or will I be coming in hot all the time?

GP Ultimate Bipe .40 + Saito .91?
 

BK:

Landing speed is more a function of wing loading than total power. With the Saito adding only a couple ounces the landing should be very close to the way it is with the 46 engine.

And personally, I like three bladed props. A 12x8 or 13x7 should fly nicely, and eliminate any clearance problems.

Bill.

GP Ultimate Bipe .40 + Saito .91?
 

My .91 with a 14x6 allows my GP Super Sportster to slow down very well with feather light landings. Without a lot of study I would think that the Ultimate's drag would be at least as much as the Sportster's. They both weigh about the same....6 pounds.....Wing loading should be about the same.......???

GP Ultimate Bipe .40 + Saito .91?
 

I built the GP ultimate bipe with an OS50sx and I didnt have enough power. I think the 91 is perfect. JMHO

GP Ultimate Bipe .40 + Saito .91?
 

Bill (and everyone else), thanks for the information. Now I've just got to get a new cowl to cut up for the .91. :D

GP Ultimate Bipe .40 + Saito .91?
 

I just finished and maidened my GP Ultimate Bipe with that exact same combo last weekend. To say the least, I was throughly impressed!!!! I decided to go with the Saito .91 when someone pointed out that it weighs almost the same as the OS 70 GP recommends.

One thing though, with all that power in a .40 make sure your re-enforce the firewall REAL well.

Mike

GP Ultimate Bipe .40 + Saito .91?
 

Mike, do have any pics of your install? Did you use a pitts muffler? Where there any odd things that you needed to do that I should look out for (other than to reinforce the firewall)?

GP Ultimate Bipe .40 + Saito .91?
 

Saito .91 is a 4 stroker, so no I didn't use a pitts muffler. I mounted it sideways with the valve covers sticking out the side and the muffler pointing down to the back. I also had to cut a channel in the bottom of the cow so the muffler didn't rub. I put a dubro exhaust deflector on it so the exhaust would hit the slant before the gear...

Mike

GP Ultimate Bipe .40 + Saito .91?
 

I'm going to go with a YS63 when I build mine.

GP Ultimate Bipe .40 + Saito .91?
 

Hey Mike,
Any stats regarding the finished weight? What prop and howze the ground clearance? Did you use wheel pants and do you fly off grass? All concerns of mine! THanks!!!

GP Ultimate Bipe .40 + Saito .91?
 

Hey Mike, what size tank did you go with for the .91? How long of flights do you get out of it with that tank? And, do you have any pictures?

GP Ultimate Bipe .40 + Saito .91?
 

I'm afraid I don't have a digital camera, so no, no pictures. I covered it in the same scheme as it is on the box, I thought that was really sharp. The difference is I used a 1" black/white checkerboard on the bottom of the wings, and the large "ultimate" sticker that is supposed to go on the top wing is missing because mine stuck together and ripped when I tried to put it on.

I've got a 14X6 Prop on it and I've had no trouble with ground clearance. I used the wheel pants, actually I replaced all the ABS parts with fiberglass. I just didn't have the patience to get a nice finish.

I terms of a fuel tank I used a 12oz tank. So far I've found it to be plenty, though I tend to only fly around 7-8 minutes for most of my flights. I imagine the 12oz'er would be in the 10-12 minute range with throttle amangement.

And finally, I've never weighed it, but I'd say it's in the 8-9 lb range, the .91 certainly has unlimited vertical but I don't think it would hover. This was my first kit build, and although I'm extremely pleased with the way it turned out it's definitely heavier then it could be...

GP Ultimate Bipe .40 + Saito .91?
 

Mike,
I how did you set up the throttle on your Saito 91? I've switched my carb around so that the throttle is on the same side as it was for my OS 46, but the throttle arm is pretty sunk back. I was thinking that I would need to do some sort of bellcrank system, but haven't quite figured that out yet. Any help would be appreciated.

GP Ultimate Bipe .40 + Saito .91?
 

Beardking,

I have three different aircraft with Saitos in each one; a Hog Bipe , a DHC Beaver on floats, and a scratch-built Spitfire. In each case I used a ball and socket system (similar to what heli flyers use). The ball is mounted to the throttle arm. I use a Sullivan Gold-N-Cable soldered into the brass threaded end they supply with the cable, but each end is trimmed as much as possible, both the soldered end and the threaded end. I only leave about 4-5 threads on it. The plastic socket that snaps over the ball is trimmed as well to just screw onto the threaded part of the brass end. This sounds alot more complicated than it actually is, so I've attached a photo of the finished cable. It should clarify everything. With this setup, adjustments must be made at the servo end.

Cheers!

Jollidude

GP Ultimate Bipe .40 + Saito .91?
 

BK:

I'm using ball links also, here's a shot of the US 120 set up.

Bill.

GP Ultimate Bipe .40 + Saito .91?
 

And a close shot of the link.

Bill.