Crash Master

I have just finished up my first and last kit - the Sig SE. I was planning on putting an new GMS .47 2-stroke on it because of the power these engines produce. However, the manual says the CG is 3.5" from LE. If I put the GMS on the nose, this thing is way tail heavy. Even with a heavy battery it is still tail heavy. I tried putting an older ASP .61 2-stroke on it, but that looks to be a bit tooo heavy. Also, I am using the GP CG machine to balance it setting right side up and I am having one hell of a time getting it to balance. It seems like I am trying to balance on the edge of a razorblade. Either I get it too nose heavy or too tail heavy. There does not seem to be any in between.

Anyone have any suggestions on a sure-shot way to balance this puppy? Is there any reason that I just can't move the CG back to say 3.75" to get it to balance with the GMS .47? Any reason why the ASP wouldn't be the engine of choice considering the weight/balance problems I am having with this bird? And if the ASP is the way to go, what is the difference (aside from the obvious power difference) between putting a heavier engine on this bird (or any tail heavy bird) and just adding some lead? Aren't you just adding extra weight one way or the other?

Thanks,

kregan

3.75 will be fine.... the 3.5 is very conservative. I actually had to
cut a trap door in the bottom of the plane so I could move my battery
back behind the radio tray to get 3.75.

If you are worried about it add a little lead for the first few flights
and then remove it after you fly a few times.

I really could not tell any diffeance between 3.5 and 3.75... I actually want
to move it back to 4 inches.... but i don't feel like moving the battery again.

kregan

BTW... why your first and last kit?

Crash Master

Would you believe that I have been working on this thing on and off for around 3 years? It didn't take long to frame it up, but I would cover it and then rip it all off because I didn't like the way it looked. I did this 3 or 4 times. Finally, a couple of weeks ago I decided on a new color scheme and covered it again.

I have found that I hate covering a plane.[:@]

Building one is okay, but the covering is just a real pain in the %$# for me. Besides, considering the very short life span of my planes (the reason I chose Crash Master), it really doesn't make sense for me to spend weeks building and trying to cover a plane that will maybe get 4-5 flights on it. Don't get me wrong, I love to build. It seems that I am actually much better at building than flying. I have over the past 3 years built and flown many SPAD's and I have much better luck with them. Seems that the simple plastic planes are better suited for my style of flying - or better yet, they have a much higher survivablility rate than the balsa planes.

With the SPAD's, I am much more comfortable with them. I guess it's a mental thing with the balsa. I am completely convinced that I am going to do something stupid and will end up taking all of my hard work home in a plastic bag. It's just me. If I could build blasa kits as quickly and as inexpensively as SPAD's, that would make for a whole new story.

As for this SE, because I am having such a hard time getting it to balance at 3.5", I think I am going to start moving the CG back until I can get it balanced. I doubt that I will go past 3.75" which should tend to make it more nose heavy and will be easier to balance with the GMS .47 on it.

fred123

What kind of covering material and iron were you using? Fred123[&:]

Rocketman612

My Feedback: (85)

That was my question.
Get some Ultracoat and then take a deep breath and dig in. Get great results every time.

Pete

FlyBlueSkies

My Feedback: (2)

I had the same problem...

Mine is covered with Ultracote and with a Magnum .61 FS, which weighs the same as an OS .46 ax, my CG was 4.5".

I added a 2.5oz nose weight (you know, the kind that bolts to the prop shaft), added 3 oz of weight under the gas tank, then moved my battery under the tank.

It balances at 3.5".

I also use the Great Planes CG and had identically the same problem.

Try adding the wieght as I described and it should balance close to 3.5".

As far as the Great Planes CG goes, you have to hold the plane level and in place. If the plane starts to shift rearward, then hold the tail slightly higher and slowly let go. The plane should balance slightly nose down.

I also balance the plane UPSIDE DOWN.

I hope that helps!

Jeff

N1EDM

My Feedback: (2)

How are you balancing your SE? I found that I had to balance mine while it was inverted. Just something to think about...

Also, I had plenty of power with an Irvine .46, so your heavier .61 might be causing some problems for you.

Just a couple of thoughts on balancing....

And, I agree that covering can be a pain sometimes, but after I built a few kits, I got faster and more efficient. You would too, if you kept with it (which I hope that you do).

I hope this might help a little bit,

Bob