Did you install wings adjusters?
How much ailerons or how mm difference between right and left wing trailing edges are necessary to make the Impact flying straight ?
Thanks

I checked my wing w/ my incidence meter. The way I check for a twist is to place the incidence meter near the root then move the meter to the tip to see if they match, on mine both panels match incidence at the root and tip and so no twist.

J-P from your discussion it sounds like one of the adjuster pin locations is misplaced resulting in one panel twisted vs. the other panel, so maybe one panel is at .25 degree and the other at 0. This can be corrected at assembly. Perhaps I missunderstand your discription. Maybe you have already contacted Comp-ARf to discuss the problem, if not I suggest you do. I have found their customer service to be ok.

Brian

Thanks Brian, but unfortunately I have checked the wings as you do, with two differents incidencemeters, and the right wing is twisted..
It don't comes from the pin location...

Well, I hope you will return the product to them and get your money back. No point in continuing with something that is incorrect. I had shipping damage on mine, Comp-Arf made it fairly painless for me by replacing the kit.

Best of luck.

Brian.

Fish God,


Do you have any pictures of your installation. I would be interested to see you engine, pipe, radio installtion. Especially your cowl and canopy, rudder & pipe mounting techniques.


Any pictures would be appriecated

Any updates since flying it abit more.

Thanks,

How much is pre installed like, the servo trays, fuel tank mount, wing tube etc.?

Patternboy,
I have pics on the camera, I just have to get them off of there and resize them.

TPH1,
there is nothing preinstalled. You have to come up with your own servo trays, and fuel tank mounting system.

Hi Guys,

Down here in Oz and 3/4 way through building. Have used Gator adjusters and DEPS for elevators. Tray area looks like attached.

Wing adjusters are just in front of the holes for the original incidence pin -- the back of the ply diamonds (or squares at an angle) just cover the original holes.

All other building issues as per this thread (oval wing tubes, oversize stab tube, cut out too much for engine area -- and I hate sanding carbon -- I put the micrometer on the stab tubes -- ID of retainer 10.01 mm, OD of tube 10.12mm).

But value for money I think it is great. About the same amount of work as the Hydeaway (except I went for the pre-painted Impact) but lots less money here. I also have an OXAI Impression -- it is certainly more work than that. Thanks for all the great input on trimming and C of G. Mine is set initially at 0 degrees stab and motor, +0.25 wings. Using OS140 RX and standard pipe. All fits neatly.

More of my build experience with the Impact can be found under the Glow -- Pattern/F3A section of an Australian forum we are trying to get going down here. This forum sometimes has minor access problems - but pesevere -- it is there.

http://www.skunkworxrc.rchomepage.com/tarmac

Happy building

Nice website! Very informative - definately helpful. Good pics too!

Thanks PepsiMike.

There are many ways to build these things -- and between the German, UK and now Australian sites referenced in this thread, along with all the US experience and the Composite-ARF draft instructions there is a great base of knowledge to call on. I certainly found it all useful.

I am also encuraged that the problems I thought I had in my kit are being experienced elsewhere -- and assume Composite-ARF are taking them on board -- or someone will have to write the definitive : 10 warnings you should read to keep out of trouble on building an Impact!!

They are minor in the scheme of things -- but still traps that could catch builders out.

David,

Excellent write-up on your Oz web site. I'm waiting on my Impact to be delivered sometime this month.

Keep up the good work!

KeithB

A couple more pics from my install that may give some ideas on some questions raised earlier in the thread. If I attach them correctly they should show a more complete version of servo tray, wing adjusters and rudder/elevator linkages in place; the wing tube as it goes in (I will put a simple bracket of some form over it to hold the tank); and the pipe mount -- this one is tough to take a photo of so there are two.

Orientation on pipe mount photos -- plane is upside down on bench, looking down the pipe tunnel from the engine end. The first pic is the Lord mount/plastic bracket attached to a block epoxied to the U/C mount at the front -- and similar at the rear -- you can see it in the second one in better focus (there is a brace across the fuz above the pipe floor taking the load). Pipe is fixed with plastic cable ties to the nylon brackets on the lord mounts (front sits exactly on the header/pipe silicon joiner, the rear on the silicone of the pipe deflector). Neat solution with help from CH.

David,

Nice site - thanks for drawing our attention to it! Did you fit stab adjusters as well as the wing adjusters?? If so, do you have any pictures??

For those who are interested I have a build thread on the go too.... www.composite-arf.co.uk . Just go to the build threads page and click the Impact - may help someone.

Rgds,
Mark

Hi Mark,

Like your build thread -- it is much more comprehensive than mine. You should let Ian Howard down here know it exists! One (hopefully not awkward) question -- there is no live link from page 2 to 3 and beyond, and I can't guess an address for page 3 that works!!

The comments/pictures I have put on the Oz site only started in response to a couple of guys wanting some basic info on pattern and the equipment we used. Ian Howard and the guys down here have been helpful -- as is the German site -- which I love when you put it through the Google language translator. You have to love that 'coal' undercarriage and a few other accurate but amusing translations!!

I didn't fit stab adjusters -- I have them on my Hydeaway (as well as wing adjusters) and never used the stab adjusters. I have enough trouble with two moving parts (wing and motor incidence) -- I am not sure I could hanlde three! I put stab at 0 degrees relative to motor.

Take care

David

David,

Erm, page 3 is still in the making that's why there is no link/page

I'm not the fastest of builders plus I'm building a 1:4 P-51 at the same time so progress is slower than usual!

Feel free to let Ian know about the site if you think he'd be interested.

I've ordered the tail and wing adjusters but may go your route and just fit the wing adjusters!

Regards,
Mark

David,

A question for you? In your picture below how do you assume the wing tube is dead level?? Do you do it by eye? Do you measure from the floor up to the tube? If so, how do you know the floor is dead flat? What are your tolerances? If one end of the tube is 1mm higher than the other do you accept that??

Thanks,
Mark

How about leveling the wing tube with the wings on, this way you accound for any variation in the placement of the tube socket within the wing.....

Hmmmm, OK I have to admit (in case you couldn't tell ) that this is my first time setting up incidences/wing adjusters etc to the accuracy needed by these model and I need some real dumb ***** questions answered!!

Firstly, I guess I have to hold the fuselage in an upright position so that the fin/rudder post centreline is at 90 degrees to a flat surface. With this done I would think that any wing/stab tubes that pass through the fuselage must have their ends the exact same height off of the work surface to assume they are at exactly 90 degrees to the fin (which is what we want)

Next , to work out the wing/stab incidences I assume I need to get the centreline of the fuselage exactly parallel to the work surface and this is where I come a little unstuck. What do I take as the centreline?? I guess the dead centre of the nose ring is the starting point of my imaginary line but where does it go back from there? Do I take it through the centre of the stab mounting tube and ensure the measurements from the work surface up to these points is exactly the same??

Sorry to ask all the dumb questions but any help would be appreciated!

Ta,
Mark

Hi Guys.

Me thinks there are no such things as dumb questions -- any question is a good question if it helps one sole make one less mistake with an expensive chunk of glass composite stuff in the shape of a plane (and I have made my share).

Here is the full (and probably convoluted) approach I took:
1) Fortunately the garage floor is about as flat as flat as they come -- so I trust it! Could be a couple of mill out, but not more.
2) The first thing I am paranoid about is where to cut holes in the fuz for the wing tube. I first checked the tube in the wing sockets (and found the need for lots of sanding to get a smooth fit), and found (as best as you can measure/level) that the sockets in the wings were relatively aligned and if the tube sat square in the fuz (horizontal and vertical) the wings would be approx square to fuz (vertical and horizontal axes). Then I did the work in the photo Mark picked up. Square the fuz relative to the floor using the fin, then slowly file out the holes in the side of the fuz for the tube (initially using just the small rod instead of the tube) to make sure it sits parralel to the fuz (vertical and horizontal -- ruler to floor, string to fin/nose). I had a nasty experience with last expensive model where the marked lines/cutouts on the side of the fuz weren't in the right place -- and messy remedial action was needed.
3) As I got the holes big enough to put the tube through I did test with wings on, but without incidence pins or some form of retainer at the back at this stage I found that hard to be very accurate -- but it was close enough. I did the same with the stab tube at this stage as well. Neither were glued at this stage.
4) Knowing the wing tube hole was true to horizontal and vertical axes, I then marked the wing adjuster positions relative to the wing tube holes with them centred at about 0.3 degrees incidence relative to motor/firewall I had done earlier. Brians earlier post on this is a smart way to do it I will use next time (#186)!! Then I could locate the servo tray around the wing adjusers etc. and get on with that bit.
5) I then pushed ahead with pipe floor in three bits, pipe mounts and all the stuff at the bottom of the fuz that needed to go in before tube/servo tray. Then I put the servo tray in (as the way I have done it it plays the role of holding the fuz in shape at the back of the wing chord where you do get some movement -- and if you ever accidentally touch a wing tip on the ground passes the load through the whole wing structure rather than breaking holes in the fuz). It plays the role they use the carbon tube across the fuz for.
6) All this done I then went back and glued the wing and stab tubes -- with wings and stabs on -- and checked and double checked alignment relative to fin on horizontal and vertical axis. (See attached photo -- measured as close as I could (to +/- 1 mm).

How accurate is it? Within a couple of mill. There is some residual slop in the wing tube/retainer that goes with being able to slide it in and out. Whether this comes into play seems to have a bit to do with how much precision you put into sanding the shape of the root ribs of the wings as they match up to the fuz. If they aren't perfect, you will always get a little movement when you tighten the wing retaining bolts onto the convex fuz sides -- and mine aren't perfect yet (and are unlikely to ever be). Having the full width servo tray in place makes this a little easier as it holds the fuz solid.

Hope this helps at least one person make one less mistake.

And keep up the great work on building the build site Mark -- photos and matching text take lots of time -- but are well worth it!



.

On incidences, I am not sure of this forums rules on product names etc!

I use one those of those laser style incidence meters. See the Oz build thread. You then don't have to get the fuz square to floor/surface all the time. You can set the meter on one surface, establish a reading, and then move it others without having to change anything and it gives you a good, relative reading.

After some debate with myself and trial fitting stabs/wings/motor, I took one of the paint lines on the fuz as my reference and set everything from there.

David

David,

Thanks for the explanation. So, would one of those laser meters allow me to set incidences with the model sat on its wheels, for arguments sake, and hence in a tail low/nose high stance so long as I had previously set the meter up 'relative' to the horizontal work surface?

Thanks again,
Mark

PeterP, what engine are you putting in yours again. I noticed you stated DZ....did you mean ZDZ? And what size?

Fredo,

I guess Peter meant a YS140 DZ

Rgds,
Mark

Hi Mark,

Thats exactly right on the incidence meter -- it doesn't (within reason) care about the angle of the fuz. You can have model sitting on its wheels and quickly check stab to wing relative incidence (or wing to wing etc.). Useful in the workshop, but also at the field when you are doing a solid few hours of initial trimming and want to keep track of adjustments you have made (particularly if you are chasing trim problems in circles as sometimes happens -- and definitely happens if you have wing and stab adjusters!!).

If something like the stabs are fixed at 0 degrees at build then that is what you set the meter on from then on. If stabs, wings and meter are all adjustable then you may sometimes need to go back to surface on the fuz (which the Impact doesn't really have -- so I used one of the paint lines)

You can do the same with the bar type meters with a 'level gauge' in the middle -- you are just wrirting down/remembering measurements and calculating differences -- and they have lower resolution.

David