reyn3545

One easy (sort of) way to weigh it is to get your bathroom scales. Then, get 2 stacks of newspapers or magazines or something like that... and make the stacks exactly the same height as your bathroom scales. Then, just rotate the scales around each of the three wheels, add up the numbers, and there you go.

You can also use this method to mathematically determine your CG... but you have to do it with your fuse perfectly leveled... put the scales under one front wheel, and equal stack of somethign under the other front wheel, and a high enough stack under the tailwheel to make the fuse level... then determine the percentage of weight on each wheel, etc.. etc.. I think it's a little too involved for a 50cc plane, but if you have a larger plane and don't have someone to help grab a wing, it's a good way to calculate. It's the same method that the air freight companies and military use every day to calculate weight distribution.

reyn3545

I did notice one thing when I was CG-ing my plane after recent repairs. Maybe it's a biplane thing, I don't know, but it's the first time I've run into it.....

the AW manual calls for the CG to be 1 1/2 inches behind the LE of the upper wing. I measured, marked the location on each wingtip, checked the CG (all good) and took off.....

My first 4 or 5 flights on this plane were so out of control that I was always chasing control problems. Eventually, I made a few hardware changes, lots of trim changes, and thought it was better. I lost the radio on the next flight, and it crashed.

After the repairs, I came to the CG part at the end of the process. Using the marks on my wingtips, it was showing to be just a little tail heavy (my preference). When I extended a string between those two points, marked the bottom of the wing, and checked the CG from the center of the wing... it was WAY tail heavy. I think that was the root of the problems I was chasing all along. I had to move both batteries up to my motor box to get everything evened out.

Did anyone else notice a difference between holding the wingtips and supporting the center of the wing? I wouldn't think it would make any difference, but maybe the cabane design has some effect?

maukaonyx

reyn, I tried the bathroom scale as you suggested. It doesn't work for me because my scale fails to register any weight on the tail wheel. It registers 8.2# on the right and left gear. The room where the plane is is my bonus room with carpet, so I can't even set the scale on the floor to weigh both me and the plane on it, and then subtract my weight. I can do that method when I get the plane into the garage though.

Regarding CG at the tips vs center of the wing...there should not be a difference. Jon

Dc2LightTech

My DA-60 just arrived and i need to drill out my prop. any make drilling jigs for the props?

reyn3545

It uses the same jig as the DA50... or, if you have a drill press and can hold the prop steady enough, just use the thrust washer for the prop as your guide.

Dc2LightTech

I don't see a jig on the DA web page. do you know where I can get one?

reyn3545

You can call DA, or I suspect Troy Built or Chief both carry them.... they are both in Florida, so it might get there faster.


http://www.chiefaircraft.com/rcmsec/...DrillJigs.html

weezle

call psp mfg. they even include the drill bit.

Dc2LightTech

gasers are a bit new(normal plane is a ultra stick ) who is PSP?

reyn3545

http://www.pspmfg.com/PropDrillGuides.html

Zeeb

My Feedback: (41)

What you were describing for flight characteristics over on that forum which cannot be mentioned on RCU, sure sounded like tailheavy to me at the time.

'Gonna teach the guys how they weigh and determine CG on full scale planes huh?

He'll probably need postal scales to pull it off on a 50cc bird and everytime I had to do a full scale, I had to pull out my book to remember how to do the computations and that was BEFORE my memory started going south.... lol

reyn3545

what memory?

I was more than a little suprized when I checked the CG from the center of the wing. Still no reason that it should be any different out on the wingtips.

Hey, if the thing settles down and flies right next time, I'll just be glad to have the problems behind me.

Dc2LightTech

thanks for the jig info, the jig is in the mail!

I have a futaba 9c (non 2.4GHz). is it time to upgrade? what are the options for power and control?

FBaity

My Feedback: (2)

Anyone have problems with this aircraft tipping over during slow taxi on grass? Has anyone tried a Graph Tech straight landing gear? My CG is correct, elevator rate 3D for taxi and still a issue when the wind is up or crossed. Otherwise the aircraft flies and lands excellent.

Frank Baity
AMA 38026

reyn3545

I haven't looked..... but could you mount the gear on backwards, so that they extended forward? I know a lot of people did this with the Hangar 9 Ultimate for the same reason.

FBaity

My Feedback: (2)

reyn, moving the gear aft would compound the existing tip over issue, the wheels need to be moved forward to correct the problem. Do you have a Aeroworks 50cc Ultimate? Clearly there is only one place to mount the main gear to the fuselage.

Frank vBaity
AMA 38026

reyn3545

I don't mean moving the gear... I was talking about turning the gear around. The "right" way to mount them is for the gear to lean towards the back of the plane. If you just reverse the landing gear to lean towards the front of the plane (you'd also need to reverse the wheel pants), then it would have little if any effect on the flying CG, but it would move more "rolling" weight to the back wheels.... keeping the tail down.

I looked at my plane last night, and it appears that the bolt holes would like up just fine if you flipped the gear over, but I haven't actually tried it.

FBaity

My Feedback: (2)

The bolt pattern will allow the gear to only be installed one way.

reyn3545

re-drill?

FBaity

My Feedback: (2)

The holes are too near each other. I am having a custom gear made with no sweep.

HelividD

My Feedback: (1)

I was thinking this also, because when I built mine, I remember I was thinking before hand about reversing it. You could always buy the carbon fiber ones and just drill those. Probably would be easier to drill?

HelividD

My Feedback: (1)

I could kick myself for not ordering the one from Valley View when I ordered my other parts. It works with the DA 50/DLE 55 and the DLE 30, so both of my gas motors would be covered. If I remember, it was pretty cheap also.

HelividD

My Feedback: (1)

And yes, lol, it's past time to upgrade to 2.4Ghz.. I have read about the DSM X, but I am a Futaba guy(after using JR 2.4 gear also, just wanted a 14)...

ggroyal1

Hey Mike,
When are you going to fly the Ultimate? Did you put the DA60 back on it? I have never been to GMA, I missed the last two warbird events.
I would like to see how it flies with the DA60.

George Royal

reyn3545

It's ready to go (again)... just waiting on decent weather and an open schedule to fall on the same weekend!