ORIGINAL: FlyEng

Bob,

Thanks again for posting your info. It will help a bunch.

I was considering putting thin wing servos on the elevator halves. But since the stabs aren't going to be removeable, I might just go with 2 small digital servos mounted in the sides of the fuse's tail under the stabs. Do you or Matt see anything wrong with this. Most specifically do you think the balance can work with out the batteries and rudder servo on the firewall. Who would have that this would even be an issue with a gas engine on the focus. Regardless, light weight is good.

Thanks a bunch.

ORIGINAL: FlyEng

MTK,

I can't wait. The power the Syssa puts out is awesome as you've determined and reported. I really like where you challenged someone to buy it and test it after they said there was no way to get the results you got. That's awesome. I think we met once many years ago down here in District 3. Probably at Ocala but maybe at one of the other meets. I was doing sportsman at the time and was asking lots of questions. I haven't competed for quite awhile but will again soon.

I just need the engine and accessories. I'm sure Todd still has his hands full getting caught up so I'm okay with it. It's only been since Christmas on the engine order. He spoke at length to my wife when she placed the order. It's hard to get her talking to anyone in the hobby let alone an RC manufacturer. Sounds like his likability and product will take him a long way.

ORIGINAL: cmoulder

Matt,

Is the 7500 rpm number with your CF-lam Xoar 18-5/8 x 13?

I don't think mine needs a nose ring, but if it adds to the quietness and efficiency I will give it a shot. Although this plane is the quietest gasser I've seen, there are still a few bumping and knocking things I have to track down, and the 18x10PN prop is pretty noisy when the tips start ripping over 8k rpm.

There is also something I noted the other day, the engine permormance dropped significantly when doing an outside loop. I don't believe it was a fuel delivery issue (i.e. fuel clunk not following fuel), but rather the change in air pressure on the little static plate (or whatever it is you call it... the plate on the carb with the small hole in it). I know this is sometimes solved by soldering a nipple on that plate and running a piece of fuel tube back into the fuse. But first I will make absolutely sure it isn't a problem with the clunk. It was cold, and Tygon does stiffen up quite a bit.

ORIGINAL: ghoffman

What oil and ratio are you using?

We are still steep on the learning curve with this engine

ORIGINAL: MTK

This shot is of the wood prop laminated in carbon. The technique is quite simple really. You simply place the assembly in a vacuum sealer and draw the vacuum

ORIGINAL: cmoulder


Matt, any chance you might do a mini-tutorial on your Xoar e-prop modification, with CF cloth sources, adhesives and technique involved?

I weighed both the APC 18x10PN and 17x13 and they are pretty hefty at 4.2 oz!![X(]

ORIGINAL: DaveL322

Slightly off topic -

Has anyone used the Syssa CF spinners? I'm interested in knowing the backplate thickness and weight of the backplate + cone for the 2.5 and 3'' spinners?

Thanks,

Dave

ORIGINAL: MTK


Bob,

I am preparing an article for publication in one of the RC magazines, preferably MA, but anyone of them that will pay, will do. Soon as I get commitment from a magazine that they are interested, I will send you the article.

There is significant weight savings that can be had. The 18x12 I just completed weighs in at 50 grams, about 80 grams less than the APCs. It is very stiff and strong as you'd expect.

There are a couple very important benefits, one of which is lower nose weight. But even more important is the significantly lower RMOI the smaller mass generates. The larger mass of the apc causes unwanted forces to the airplane which vary continuously throughout rpm changes. Lower rotating mass reduces these forces substantially and even guys with less flying experience (relatively speaking, probably not rank beginners) can tell the difference. Spool up and down become easier, crisper. True, flywheel effect at idle suffers but it matters very little in an ignition set-up.

That's why I have been most excited by this development. And the Xoar props make the transition to hybrid, true composite props easier because there is little carving involved by the user. These props were not available even as late as spring last year, to the best of my knowledge. I received my first ones around October last year.

Matt

Matt,

The reduction in spinning mass outfront does make for a surprising change in handling as you say. Remeber Dynamics that course in school right after Statics. If folks don't believe the effects they can try it themselves. Try holding the plane securley while its running at a fair RPM and sharply repoint the nose into a different position. You'll feel the forces trying to deflect the movement of the nose from the straight path you're wanting it to go. An exageration of this is the spinning bicycle wheel or the rotor on helicopters. When the wheel or blades are rotating, it is quite hard to rotate the frame or center out of plane with the rotating disk without getting unwanted results. Most people get this i'm sure. Trade the rpm of the spinning prop for the mass of the tire and wheel and there you go. Makes one wonder why the front end our planes don't rip off more often than they do. This is especially true when considering guys do repeated walls and other high G maneuvers.

I'm glad this came up because I've been wondering for quite sometime as to why pattern flyers don't use lighter weight props. I figured that our planes with long tail moments meant most would end up tail heavy. Consequently, i guess there was no reason to develop light weight props for pattern use. If you had trouble with weight you went for a light weight spinner. I like the idea of light weight props...... Makes a bigger Syssa engine even more practical.

You'll feel the forces trying to deflect the movement of the nose from the straight path you're wanting it to go. An exageration of this is the spinning bicycle wheel or the rotor on helicopters. When the wheel or blades are rotating, it is quite hard to rotate the frame or center out of plane with the rotating disk without getting unwanted results.

ORIGINAL: cmoulder
having a prop that weighs less than half as much as these 120-gram APC's has got to be a good thing.

ORIGINAL: tsyssa

3'' spinner cone and backplate weigh 1.4 oz or 40 grams