RE: BME Edge?
 

Oh, man that sucks !!!! I sure hope the CG is wrong or else the planes is worthless! If you have to add all that wieght back just as well to buy a WH! Let us know how it comes out !!! I hope the CG is wrong [:o].


Chad

RE: BME Edge?
 

Put your measurements in this cg calculator and see how close it comes. If it's way off, then maybe there is a misprint.

http://www.palosrc.com/instructors/cg.htm

RE: BME Edge?
 

1)Move the rudder servo forward as possible or
2)Move the elevator servos forward or install them in the fuse with MK bellcrank? That's what i did on my CA 24% Extra300L to balance the CG. Works well

I agree, 12oz of dead weight in the nose can be a problem !
Good luck.

RE: BME Edge?
 

This most likely is going to sound dumb but what is %MAC? From what I can tell you need it to use the CG calculator but to find the MAC % you need the CG, Please Help! The root cord is 20" the tip is 10" no back sweep, 85" wing span. [:o]

RE: BME Edge?
 

Hmmm... interesting...

I calculated the MAC (mean aerodymanic chord) and it equates to 15.33"

3.5" back from the LE would offer a 23% C.G.

4.6" would be 30%

5.5" would be 36%

Not sure how that equates overall to what it should be flown at, but seems to me the 30% would be the starting point and 5.5 be the rearward CG...

Still check with Max...

When in doubt, add the weight temporarily and remove some til you are happy with it...



Ronk1,

Where did you install the pull-pull servo? Got a pic of the install? If tailweight is an issue, you could move that 2 oz in front of the wingtube (near CG and save 2 needed in the nose)


What about the engine/cowl placement... did you move the cowl out as far as feasible in order to mover the engine out that far?


You could lose a little tailweight by drilling out some of the tailgearplate... pretty hefty there and you only need some meat around the screws... You might save 1/2 oz there and 2-3 in the nose...


What servos, batteries, tank, etc. are you using?

RE: BME Edge?
 

It's actually 19.75" Root, 9.75" Tip and 38" length with an MAC of 15.33" (0 sweep)

RE: BME Edge?
 

I'll be mounting the cowl so it laps over the F1 former by 1/16"... this moves the engine as far out as possible helping with balance.

I'll drill out some material in the tailblock.

Use a graphtec SMALL (up to 15 lbs) tailwheel.

Mount the rudder servo as far forward as I can... a quick check of the lineup shows I can run the cables straight and place the servo in front of the wing tube just behind F2. This will actually place the servo ahead of CG...

I'll shoot for 5" back from the LE to get a C.G. of 33% MAC.


I think this should do it just fine, but if not, I'll go pull-pull elevator... a single 8611 will dual cables running to each elevator...

RE: BME Edge?
 

You can start off with a 30% to 33%MAC.

Why do you say it's 38" length,?????

RE: BME Edge?
 

Because that is the length of one wing panel... 38"

RE: BME Edge?
 

Test flight in! CG at 5" to 5 1/4", this is were it should be. This airplane flies great:D! I don't know where 3.5 to 4.5 came from, it would be nose heavy. Even better no pull-pull elevator or added weight! Landings are slow and controlled, inverted flight a touch of down and I do mean a touch. No photo's today, sorry next time[8D].

RE: BME Edge?
 

You should use half the span, not just the wing panel. The fuselage is counted in the span.

RE: BME Edge?
 

Keys to balancing the BME Edge with a light weight 50 class engine.--- Drive hub 6 7/8" out from fuselage sides. The firewall is glued to the sides out as far as possible, flush with left side then 2.5º right thrust not three. Battery's, throttle servo, rudder pull pull as far forward as you can (OK for elevator servo's in tail) and a light weight tail wheel. You should end up close to 5" CG from front of wing. I know it calls for 3 1/2 to 4 1/2 but 5 to 5 1/4 in. works out very well;).

RE: BME Edge?
 

ronk1

What exhaust did you use?

RE: BME Edge?
 

The factory muffler that comes with a FPE. The weight listed for FPE engines includes the muffler and ignition. The reason I mention this is for comparison.(DA's and BME's are weight without). Any three of these engines would balance close to the same. The BME I would use the Pitts muffler and you will need a motor mount.

RE: BME Edge?
 

You're right... my bad... this makes it even easier to get the balance...

The length would therefore be 42.5"

30% MAC would be 4.5" from LE

33% wuold be 5" from LE

35% would be 5.25" from LE


So it's no wonder Ronk's did well...

RE: BME Edge?
 

Ronk, how about a little more detail?

Coupling? Slow speed traits? Flatspins? Wingrock in harrier? Inverted flight... pitch up or down? Landing?

Come on now... be a good ROnk and fill in the blanks eh? ... :)


BTW... Why did you opt for a 2.5 degree right engine thrust instead of 3?

RE: BME Edge?
 

Ronk...

One other question... snapping on elevator... I'm sure it will, but how much can you get away with?

RE: BME Edge?
 

I will get back with more details after I have a chance to"put it through its paces". What I know so far is slow speed stall is very slow the nose drops slightly but controlled a little power and of you go. Inverted flight is the same as upright, it does not fly any different other then its needs a touch of down elevator. At slow speed the elevator is very effective. Landings are slow but you could get yourself in trouble without expo in the elevator. This plane should "Wall" great. I had a small mechanical problem (my fault), so not much flying time. I should be able to fly it tonight and have some photo's and more info. The reason for 2½º right thrust 3º seamed excessive and would not have matched the cowl;).

RE: BME Edge?
 

Got my Edge in. Fedex decided to take the pleasure to crush my wheel pants, and break one stringer in the under nose, as well as put crinckles in the turtle deck from being crushed. The plane can still fly like it is. Looks great though.

RE: BME Edge?
 

Them losers... sorry to hear about the damage... glad tho that they can be easily repaired or replaced... Give BME Aircraft a call... I'm sure they'll get the pants taken care of.

RE: BME Edge?
 

What size is the wing tube ?? 1-1/4 or ??

RE: BME Edge?
 

I called BME, but Max was out. Sunday afternoon he called me, we disscussed it. Im sending damage pics tonight to him. He'll make a claim and see if we can get anything out of it. The fact that he called on a sunday ,well, thats great[8D]:D!!!!


Max also made the comment of switching to another company other the Fedex, guess hes Fedup, lol.:eek::)

RE: BME Edge?
 

That's a shame. I have had things damaged by UPS and have had good luck with FedEx, you just never know. I'm sure it will be taken care of.

RE: BME Edge?
 

if i had spmthng to measure with, id get that measurement, but, i have nothing right now, im starting over , been living on my own a month now.

RE: BME Edge?
 

The wing tube looks to be 1 1/4"...