I'm in the process of building a GP Giant Aeromaster with a Zenoah 62. I have everything purchased and was wondering if anyone knows if a Slimline SLI2100S pitts style muffler will fit.
Any help would be appreciated.

I built one with a Brison 3.2 with a Slimline Pitts muffler. I had to cut out a fairly large portion of the firewall at a 45 deg angle to clear the chamber on the muffler. I would think it would be worse with a G62 being a slightly larger engine. The biggest problem though is the fuselage is very narrow compared to extras, caps, edges, etc. I had a tough time mounting two tanks, smoke pump, ignition module, ign battery etc. If you still have the magneto ignition that should help a little with the mounting of the components (or lack of) The cowl is also narrow, The muffler sticks out slightly on the left side, where the wrap around is to connect to the exhaust port. It doesn' t look bad, its almost flush with the cowl, but I had to cut it out to prevent chaffing, so you can see the side of the muffler with the smoke tap and tubing. I also made a hatch behind the firewall on the bottom of the fuse to access the ignition module and battery. Its a strangely shaped hatch due to all the cutting on the firewall, but it came out pretty good. Mine weighs 19.5 lbs.

Brian

Just got mine in the air.....you'll love this badboy......it flies awsome....

I started with the Bennett muffler on my Giant Aeromaster/RCIgn G62 combo, but cut a bigger hole in the cowl and used the production muffler after a few flights because the Bennett was just too loud. The plane does not look too bad with the cowl cut around the standard muffler. Cheap and effective. If you use a Pitts style you will have to rework the firewall area for more clearance.

Plane flies wonderful.

I thought about using the Pitts style muffler in the beginning but decided that I was still going to have to cut a hole in the side of the cowl anyway. So, I used a J'tec muffler instead. It was extremely noisy and leaked gunk all around the the edges of the muffler. It is a two piece design and screwed together. IMO it is a poor way to build a muffler.

I thought that you might like to see how I built a quiet muffler out of .030" (20ga I think) steel sheet and brass tubing. It weighs 7 oz which was about the weight of the aluminum muffler.

The Giant Aeromaster with a G-62 is a great flying plane. Mine came out at 20.25 lbs.

Ken

I also have one it is one of my favorite planes. The US .41 engine is mounted on mine and it has probably enough power--still would probably rather have the G-62 as more power would be fun. The US .41 does, however, fit the cowl very well. Very little hacking of the cowl is needed and the stock muffler fits perfectly. Had to cut out a small hole to clear the the ram air carb extension and a minimal amount to clear the head. Probably needed this much anyhow for cooling purposes.

I am having to use right much down trim for this bird to fly right. Anyone else notice this. With this much down trim it would seem that the CG is too far to the rear, but it doesn't fly like that.

Sam

Sam, I started out with a similar problem of needing too much down trim. Also my plane was a little too twichy in pitch. I solved the problem by adding a couple of washers to each rear cabane strut and readjusting the interplane struts. This gives about 1 degree of negative pitch to the upper wing with respect to the lower wing. I also added enough weight in the tail to allow the plane to fly level with neutral elevator trim. The plane flew good before I did these mods but flies much better now.

Ken

I dont understand why you guys would pick the Zenoah G62 for this bird. It seems to me a good small ignition gasser would be lighter and pull much stronger. Such as a MVVS 2.15 35cc or a BME 44 or ZDZ 40 etc. The G62 weighs in @ 82 oz's, what kind of tail weight is required to balance this beast? The MVVS 2.15 weighs in @ 55 oz's, the ZDZ 52 (I think), BME 44 weighs @ 43oz's. Not trying to knock any of you just curious, as I am looking for a larger Bipe.

Greg, in my case I already had a G-62 from a previous airplane. When I started researching information, photos and reviews, on the Giant Aeromaster I found that the G-62 was the predominant engine used in the GA.

I used about 2 oz in the tail for balance and that's because I was afraid of a tail heavy airplane and took several steps to lighten the tail area. Guess I over did it. There are also 3 HS-605 servos in the tail. If I had put in one of the 43, 52, or 55 oz engines then I would surely have had to add nose weight.

There is another consideration on this airplane for using a US41 or G-62. It has a narrow fuselage and there is very little room to put a battery and ignition system in front of the firewall and it's a pain in the --- to put one behind the firewall. I mounted my G-62 on 1" dia hardwood standoffs so that I could put the CH Electronics Jump Start between them. Makes starting a breeze with little added bulk or weight and no battery to carry along.

The more "modern" engines on the scene now are really great, however, for a long time I have noticed in the IMAA magazine, High Flight, event reports that the G-62 is by far the predominant engine used. They are not much cheaper than the comparable modern engines. Sure makes you wonder why they stay so popular doesn't it?

By the way, as soon as I break ground with the GA, my old G-62 will take vertical out of site if I wanted to go that far.

Ken

Ken

What prop are you using. I'm just finishing my GA with a g62 as well. Right now I have a Zinger 22X6-10. I'm really looking forward to flying it. It is my first gas plane. If you have any other tips on flying it I would appreciate it.

Craig, I think that you will find this to be a very easy airplane to fly. It doesn't have any bad habits. It was designed many years ago by Lou Andrews and he really knew what he was doing. The guys who bumped the design up to the giant size version also did a great job.

I recommend that you look at my post above on the wing incidence modification. If you've been flying RC for a while you shouldn't have a problem.

Now I need help with a pesky problem on the GA. No matter how I tighten the bottom wing on the wing saddle I have a problem with a sleight charing of the wing where it meets the wing saddle. This is caused by vibration. This is near the main spar area. I tried using 3/8" wide by 1/4" thick foam tape on the wing saddle but all this did was destroy the tape. I next tried Automotive GOOP (similar to Zap-A-Dap-A-Goo) on the wing saddle. This seems to be an improvement but is not the total fix. I think that there needs to be a plywood piece in the wing which would extend up into the fuselage and come in contact with the fuselage sides. This would prevent the side to side motion. The four nylon screws which hold the wing on don't prevent this motion. Maybe a dowel pin would help. How bout some thoughts on this.

Ken

Ken, I don't have the chafing problem with the lower wing that you do. Probably is because I am using the US .41 which does not produce as much tork as the G-62 or as much vibration. I think you have hit the proverbial "nail-on-the-head" with your fix for the down trim problem. Great thinking! I was almost sure that this had to be a wing incidence problem, but since this is my first biplane I was not sure how to fix it. The interaction between the two main wings is still somewhat of a mystery to me. I will try your remedy though. Thanks very much for your help!

Sam

I solved my lower wing chafing problem by fasteneing some 3/8 square stock to the top of the bottom wing. These pieces are spaced so they just fit inside the fuselage sides. Keeps the wing from shifting sideways, and they help you align the wing when you are putting in the bottom wing bolts. Since they are inside, there is nothing to mar the appearance when the plane is assembled.