RCISFUN

My Feedback: (44)

You have to love those low passes, my buddy did the same thing over a year ago, look at post #8 in the following thread.
http://www.rcuniverse.com/forum/m_63...tm.htm#6300402

He was able to "Trim" both booms

His repair was quite simple, glue in a block of balsa to the bottom, reshape and cover, now you can't tell it ever happened.

RCISFUN

My Feedback: (44)

Here is a shot from our field in Titusville PA a couple of weeks ago.
It was sort of an impromptu Boomerang gathering, we had the whole Boomerang Family in attendance, (XL, Elan, Baby and the Sprint), my Formost was the half brother as it contains the CF rear spar from an XL.

AVIOJET

Felix, I am thinking to fit some kind of rollers at the bottom of my BB's tail booms.

B.R.

.Jesus

akaram

Guys,

Would like to share with you the photos of my Boomerang which I maidened this Saturday. I have a Wren Supersport on it, I loved the plane, it is a joy to fly and so easy and stable. One problem I have is that when I trim the elevator at low speed, the plane climbs at full throttle and on the contrary if I trim it to fly straight at full throttle it sinks a lot at low speed. I read before about some of you having this problem but dont remember how it was solved and it is a burden to read all the thread again (almost impossible). Would appreciate any input on that.
I put a total of 4 flights on it this weekend, on the 4th flight the landing was a bit hard, there was a strong headwind and the plane almost stopped at 1 meter over the runway and dropped down. After examining the center wing section I found 4 cracks on both sides around the servo wire access hole caused by the weight of the tailbooms which transmitted the force on impact through the dowels. Had anybody have this happen to his boomerang ? What is the best way to fix it ? I feel I should remove some sheeting from the bottom of the center section to be able to strengthen the 2 outside ribs ! I am thinking of adding a 2nd dowel closer to the leading edge to distribute the force and lessen the stress on a single point.

KC36330

shim the front of the turbine up with a washer.

akaram

One washer will be enough ? or should I start with 2 washers ?

ltdorn1

My Feedback: (39)

for the trim change....

1. make sure the stab is fully and truely seated in the two booms.
2. if it is seated completely flat on the booms, then you need to shim the front* of your engine up a bit. Try one or two thin washers under front bolts. you need some down thrust on the turbine.


Lawrence

highhorse

My Feedback: (2)

re-read the thread...Im know I've seen several posts exactly answering your question. U may find a poster with your same engine etc. Different engines require more/fewer washers, but you DO need to shim.

Ayrtonsenna

My Feedback: (1)

One other thing- have you checked the indecence on the stab, tobe honest, I needed alot of up elevator trim for straight and level flight, and after checking the C/G again I then found that the stab was sitting at +2 degrease.
Once I'd reset with washes ( 0 degrease ) I've removed all the trim, and it now flys straight and level through all throttle settings.
Good friend who flys a BB found he had the same problem-

Ants

akaram

Senna, I thought of that as a possible problem, but how can you measure this incidence, looking at it from the front and from behind and the side and from far away does not reveal any defects, is there a special tool you use to exactly measure incidence ?

nt flyer

Hi Akaram. Try this one http://www.robart.com/how_to/incidence_meter.aspx

I used a tapered plywood shim on the top of the fin, and have it set to zero. I have no issues with trim change!

Cheers,

Greg

akaram

Thx nt flyer, looks great, I put it in my wish list great tool to have

akaram

I will wait for that tool to arrive and check the stab. I am grounded anyways waiting for the front retract replacement parts to arrive which Sandor was kind enough to ship immediately and for free !!!

afftced

My Feedback: (8)

Guys,I need top hatch and canopy. It fell apart from the air.

B58

My Feedback: (43)

I believe that you can get one from Patricia. I had to replace mine a year or so ago. Bob

PeterDays

Has anyone seen this Boomerang on floats?

Check it out:


http://br.youtube.com/watch?v=k6c-LweM-VM&NR=1

akaram

Ayrtonsenna and nt-Flyer please let me know what turbines you are running and if you have shimmed them too in addition to shimming the stab.
I received the incidence meter and found the stab to be sitting at 2 degrees, I shimmed it at the back to get 0 degrees + I shimmed the front of the turbine with 2 washers.
Flied it and found the problem to be less pronounced now but it was still there, I am wondering if I overdid it. Maybe I should remove the shims from the engine ?
What I didnt like most after those modifications is that now during inverted flight to fly level I need to apply at least 50% down elevator which is toooo much !!!

nt flyer

Hi Akaram. My Boomer has a PST600R. No shimming on the engine. My tail was also about 2 degrees out, which is where I made the shim.

Where is you C of G?

Cheers,

Greg

akaram

My CG with just the UAT full is at 185mm from the LE where the wing meets fuse. Where is yours ?

Ayrtonsenna

My Feedback: (1)

Hi Akaram,
I'm running a P70- with no engine shim, my tail was also about 2 degrees out- but after packing the "trailing edge of the stab up"
I now require no trim for straight and level flight- thanks to Greg for pointing this out to me!

Ants

akaram

Senna, after you shimmed the stab, did you notice that now you need too much down (like 60%) to fly level when inverted ??? Before shimming mine flew inverted great requiring only a tad of down, Now after shimming I need loads of down to keep it level in inverted flight and the tendency to climb at full power is still there !!! much less than before but there !!! it is really annoying !!!

Ayrtonsenna

My Feedback: (1)

Hi Akaram,
Once I shimmed the stab, I removed all the trim, and she now fly's great! even when its inverted, I didn't touch the engine mount (P70) only the stab

To be honest, I'd start checking everything again, you may have mist something-
Start with the wing incidence to the stab again, I'd also check the C/G, is it possible you may have some positive up on both your ailerons?? make sure there both neutral when the models switched on-

Any ideas Greg?

Hows that F15?

Ants

akaram

Good idea, will check that, I have them ailerons aligned with the wingtips, will check maybe both are down a bit causing this effect.

siclick33

I'm sure I've read this somewhere but can't find it.

I have glued the wing to the fuselage and believe I have made a pretty good job of it. What have you done to the inside to reinforce the join? Is a bead of Hysol enough or do I need to put a bit of cloth and resin or fillet across the join?

Thanks

ThomasP

On mine, removed the covering, glued the wing assembly to the fuselage (used 30min epoxy) after 24 hours applied a substantial fillet of Hysol all the way around, no problems after two years