famousdave

My Feedback: (61)

I just finished up a BME edge and I am having a hard time balancing it. It appears to be a tail heavy pig and I am quite disappointed so far.
The advertised weight was 15.5 - 16 with a DA50, mine is just over 17 pounds.

The manual states that it should balance at 4 to 5 inches from the leading edge, but with nothing to move further, mine balances at approximately 6" aft of LE.

All my "tribal knowledge" in plane building says 30-33% MAC or worst case at the center or just aft of the wing tube
I usually go with this guideline as have seen many manual errors over the years.

If I use one of the MAC calculators, 33% MAC is 5.61" on this wing - which is just forward of the the leading edge of the wing tube
I don't believe too many of the MAC calculators however especially on edge wings with zero sweep loaded...

If I go with the wing tube method the center of the wing tube is 6.5 inches from the wing leading edge, If I balance there it would be a full 1.5 inches aft of the manual suggesting a very tail heavy setup.

After everything was installed, I ended up with a CG right at 6.0 inches (i.e. just AT the leading edge of the wing tube). On every plane I have set up in the past that has been a good maiden flight setting.

So I went with the balance as is and flew the maiden.


If flew snappy to me, I was playing with the trims more than I wanted to and at low (i.e. landing) speeds it would get snappy and drop a wing. I did not roll into a vertical banked turn to check CG in flight, but I did roll inverted.
She climbed like she was tail heavy.

It was snappy enough to make we want to verify everything before I fly again. I landed no problem, but it was anything but a floater as everyone has said this plane is.... and I had to really be light on the elevator.
It did hover quite nicely though as a tail heavy pig should.

Anyone have one of these and had similar issues???

I have already used very light weight components aft and I have nowhere to move anything more forward. I have already drilled and set the cowl... moving the engine forward is not an option either.


I would have to add one pound of dead weight to balance at the CG in the manual... and then what's the point... there goes any 3D performance..
it just doesn't make any sense to me....


DP

Thunderbolt47

My Feedback: (8)

DP, are you using P/P on the rudder?

SitNFly

My Feedback: (54)

DPig,
Look at this thread in ARF/RTF....http://www.rcuniverse.com/forum/BME_...1753711/tm.htm. Quite a few of the posts complained about being tail heavy. Hope the link works. Just look for BME Edge in the ARF/RTF forum.

famousdave

My Feedback: (61)

Thanks guys...


P/P 8611 stuffed as far forward as possible (like damn near touching the fuel tank!!)... used a y-harness and soldered connections to shorten amount of wire / connections to the two elevator servos... canned the original tail wheel and used an Ohio Superstar (2oz) lightweight instead.... Also used lightweight cables and ferules, etc... still tail heavy...

I'll check out the thread mentioned...

I actually put it up on the balancer today again... it would take nearly 2 pounds to make it balance at 4" and over one pound for 5"... mine balances at just over 6"

33% MAC is 5.6" on that wing if you believe the calculators...

I think at 5.6" she would probably fly fine. I am an RCH over 6" right now....


Looking to get out the hole saw for the rudder and put on a metal spinner if the advice from BME does not come back positive...
It will KILL me to add weight to a 17+ pound bird... all of my equipment is up forward of CG right now... even if I took out something it would not help!!!!

I am already really PO'd that I couldn't get closer to 16#..
DP

wingburner

My Feedback: (17)

Man am I glad to read your post.Sorry for your troubles, but my finger has been within an inch of hitting the purchase button tonight.I will choose another aircraft.It's sad that many planes are advertised at a certain weight and then don't balance out.I was choked at having to add a pound of lead to my 35%.I later removed it with no ill effects,but adding 1 lb to a 28% is ridiculous.Hope you get this worked out.

GreaTOne_65

That is not what I wanted to hear, desertpig. I bought a Lanier CAP 232, and that is exactly the way that airplane flew. I took it back to the shop moved everything to the front, and it still took a pound and a half to balance. I couldn't believe that was right so I took it back out the field, and guess what? It was still nearly unmanagable, so I took it back added the 1 1/2#, took it back to the field and it flew better, elevator stopped hunting, but now the damn thing l flies like a streamlined ROCK! Took the brute back home unloaded the lead, took those damn servos out of the tail, installed a pull-pull on the rudder, and push rods on the elevator, and it balanced right where it was supposed to 1 1/2" in front of the wing tube.

So thank you for the heads up, I will not even try the servos in the tail job on the BME, I'm just going to plan on building push-rods. I don't need the aggravation.

Dale

Y N C

No balanceing problem with mine with a brison 3.2 at 17.5 lb, all around excellent plane.

dirtypool

My Feedback: (6)

Can you add an inch or so to the DA-50 standoffs (or get longer ones) to compensate? will the cowl still fit?

JoeAirPort

My Feedback: (41)

Oops. You already have a light tail wheel. Nevermind.

Thunderbolt47

My Feedback: (8)

Have any of you guys seen the review in FlyRC. They reviewed a BME Edge 540. Their plane with DA 50 and Formeco batts. came in at 238ozs. According to my redneck math that's 14.875 lbs. Knowing FlyRC would never pump sunshine up anybodies rear and kiss the manufacturers butt. All of you guys must have a brick in yours somewhere. Oh, and no mention of the tail heavy problems you all have had.

ptgarcia

My Feedback: (36)

Yeah, and the 27% Aeroworks Ultimate they reviewed came in at 234 oz, that's 14.625 lbs. Mine is an easy 17 lbs. with BME 50 and single 4400 mAh Li-Ion on receiver and 1650 mAh 4-cell on ignition! These guys are full of s-h-i-t!

Thunderbolt47

My Feedback: (8)

I just get Fly RC for the pictures. If you want truth, RC Report

famousdave

My Feedback: (61)

Ahh.. so what your saying is that if I add a little BS to mine I can save 2 pounds too !

hmmmmmm


Maybe FlyRC would like to buy some prime beach front property I have for sale ..... in Arizona..

DP

Thunderbolt47

My Feedback: (8)

I hear B.S. gives off I slight odor. Who know's it might be ligter than air. Maybe that's where the two pounds went!!

Gerry Dale

My Feedback: (22)

I have just completed my BME Edge 540 to the stage of balancing. I have used a ZDZ40 RI with a BCM muffler and 2000 mah NIMH batteries. With elevator servos in the tail and with a CF wing tube and 5 oz. CF landing gear it required 2# of lead positioned in the center of the motor standoffs (13.25" forward of the CG.) In order to balanace at 4 3/4" (my objective) I am moving the wing tube back in the fuselage 2 1/8". This is easier than it sounds and will have little effect on the performance. My all up weigh after removing the 2# of lead will be just over 15#. I don't believe this plane will be much fun at 17#. Make a template of your current wing holes and then move the template back the desired amount. You'll need to plug one of the lightening holes at the rear and the aileron servo wire hole to accomplish the task.