Hi Jim,


I concur with Matt. As far as I am concerned this is the only way of assembling a model with guaranteed results. You may fluke the occasional build but nothing beats good preparation and having the right tools for the job.

I have included a couple of other photos which show my wing supports during the gluing phase, this keeps everything in place without risk of movement during the night while epoxy dries. I have used some of those adhesive rubber feet attached to the 1/4in nut to rest the wing on. Infinite adjustment by screwing the nut along the threaded rod.

When you have everything square and centre lines you can rely on I use the trusty dressmaker measuring tape to confirm everything. put a screw on the centre line and pull as much as you like without pulling the fuse with you.

Worth removing as much material from the tail post as you can without compromising strength. Weight in the tail of these birds is something you don't want.

I just realised they never gave me the outer tube for the tailplane carbon spar. I guess I will have to wait until next week to get one. I guess there is plenty of other work to do.

wow, all of your attention to detail and time taken to make everything true and straight, not to mention clean and efficient is admired by this kid! thanks for sharing!! i'm picking up a lot of good tips with threads like these!! (just hope my thumbs can remain as calm, straight, and true and my ship! )
thanks again for sharing your tips!!!

Peter, how are you establishing the wings perpindicular to the vertical stab. I see your adjusters to align the wing but curious whether you measure from your board up to the LE and TE of the wing.

Thanks

Hi Guy's,
Just a quick update, I've weighed my stock rudder with the l/e removed and a new balsa l/e installed and it came in at 100g!!!!!!!
Hence I've started the build on a new one from balsa, so far the weight is 12.5g but I've yet to add the counterbalance tip and the bevelled l/e [8D].

Thanks so much to you all for the push in the right direction, I'll update soon with pic's & stuff!

Kind regards,

Andy.

Hi Guys - AWESOME thread. I've dutifully read ALL the posts. I am now preparing to hang the wings and stab. Instructions call for 2-2.5 degrees of down thrust. However, this is not built into the plane as far as I can tell. 3 of 4 of the horizontal stab locations match when measuring vertically from my building surface with the tail blocked up 33.5 mm. with only 1 being a about 2 mm high. However, the down thrust in this setup is only 1.5 degrees. Also, the right side wing tube hole and aft pin are about 3 mm lower than the left side.

Essentially, if I block up the tail 33.5 mm as suggested in this thread, 1 horizontal stab point is off (I can fix that), however, the left side of the wing locations are low 3 mm, and down-thrust is only 1.5 degrees. If I raise the aft end of the fuse to get 2-2.5 degrees of downthrust, then the wing and stab locations are off is X and Y directions?

What is the best thing to do? Block up the tail to get the down thrust (2.5 degrees)? Or, block up the tail where at least 3 out of 4 of the stab locations match, adjust the 4th to match the three, and let this be the "zero-zero" reference, then add down thrust to the motor, and reference the wing incidence from this position????

Thanks,
Jim W.

Hi Jim,
If you go to pages 8 & 10 of this thread, you will see how both David Gibbs and myself have set our Impacts up. Essentially the set-up's are the same and really suit the model!

Enjoy [8D]

Andy.

Thanks Andy,

Checked and it seems that 0 engine, 0 stab, 0.25 wing, and carry a little down elevator.
Thanks,
Jim

Peter, what exactly is "Depron"?

Eric, very clever use of the combo former/foam holding box...kill two birds with one stone!

peter,
Pray tell, where did you get the CF horns?? Pretty please....

Eric.

Today was a busy day of testing in southern NJ.

For anyone who has not flown their IMPACT yet you need not have any trepidations. I was delighted from the moment it left the ground. The only hard job was setting up the OS mix carb on a 42F March day.

The only flying-mix that I could see that would be needed was a tiny bit of proverse roll correction, and that only showed on a field long KE test. (probably about 2%)

Thanks to a first class incidence-setting job by George Asteris the plane flew great from the outset. Some planes just feel right as they leave the ground. This is one of them. Thanks to all of the throw-setting advice in the thread there was no real need to change anything. Spins were rudder and elevator only, The 2 turn reverse was as good as the pilot's timing.

It has the signature Pterodactyl "screech!" when you snap. Add your own "whoops"....

Regards,

Eric.

Congrats Eric!! Mine is getting the Hacker setup. I saw Brian Billings fly this weekend in Ocala. The plane has a great presentation to it.
Jim W.

Hi Guys,

Sorry for taking a while to respond.

Brian:

I first position the fin so that it is perpendicular to my flat building surface. I then adjust the height of my wing supports so that the wing is parallel with the board. I found that when I positioned the wing to the fuselage that the gap was tiny so only a small amount of sanding was required. Distance between building board and trailing edge was perfect when I did it this way. I think it is important you have a setup which keeps things exactly in this position while glue is drying.

Eric:

The horns are the original brown units supplied. I simply roughed them up with 80 grit and then mixed some epoxy and put some 5oz carbon cloth on a sheet of glass treated with release agent. This was left overnight while compressed between another sheet of glass. In the morning I simply cleaned up the edges and presto. I would have used 3-4 oz cloth if I had some on hand.


Jim:

I positioned the fuse that the distance between the front underside of the engine cowl flange and a distance exactly 37mm below the centre line of the tail plane wing tube as being my datum line. I set my jig to hold the fuse in this position. I also had to adjust the front fuse support on the jig to tilt the fuse slightly to get the fin vertical. The tail plane was fairly close to 0-0 at this point but I found the wing anti rotation pins to be way out. I ignored their markings and made my own. I would have had .3degree negative incidence on the wing if I had used their settings.



Eric:

Do you know what reference datum line was used in your model. Secondly, are you carrying any elevator trim and what was your final flying weight?

I cant wait to get mine flying.


Peter

Hi Jim,
During testing, I noticed that the underside was hard to see. I had used a white band about 10" wide but it did not help with the visibility. Today I sprayed a band of flame-red about 8" wide one each wing that should provide a better contrast with the yellow and more recent white band. Flame-red is pretty close to the pre-painted version colors.

I noticed that the wing roots have sharp edges that cut into the fuselage sides with engine vibration. I have since added some 1/4" balsa spacers at the front of the root rib to provide more of a flat surface area to press against the fuselage side. The wood can be sanded flush. In a similar fashion the wing bolt has been supported to avoid the fuselage sides bowing out as the "wing" nut is tightened.

Regards,

Eric.

Eric:

The horns are the original brown units supplied. I simply roughed them up with 80 grit and then mixed some epoxy and put some 5oz carbon cloth on a sheet of glass treated with release agent. This was left overnight while compressed between another sheet of glass. In the morning I simply cleaned up the edges and presto. I would have used 3-4 oz cloth if I had some on hand.

Do you know what reference datum line was used in your model.

Secondly, are you carrying any elevator trim and what was your final flying weight?

I cant wait to get mine flying.

1. The horns just looked so great. I would willingly buy CF horns if anyone was making them?

2. George Asteris used the IMPACT instructions and they were right on.

3. The elevator trim is dead-on with the stab tips.

4. It was heavier than I expected. I am using an OS 1.60 etc so the AUW with 24 oz tank, heavy Mustang 3-1/2" spinner and supplied U/C was 10 lb 12 oz. Expect it to be 10 lb 8 oz with new spinner and 16 oz competition tank etc.

Regards,

Eric.

Eric....

My offer still stands incase you want to adopt another son. <G>

Looks good. Are you going to be down towards D2 way any this year for any contests?

Couldn't agree more on visbility -- flame red would work well, dark blue stripes underneath give a good contrast to the yellow and also work well. The pre-painted scheme on the top of the wings also becomes less than clear at a distance in some conditions -- a mate of mine has painted out the Impact and some of the fussier stuff on top of the wing to create a clearer contrast/shape around leading edge line and triangle shape on the inner section. Makes it much easier/quicker to pick up orientation in more difficult visibility conditions.

[I just checked -- he has whited out the section with 'Impact' on it between the blue stripe along the front of the wing and the orange around/at the aileron hinge line. He has also painted out everything inboard of the diagonal blue stripe running from the front of the wing close to the fuz, to the back near the inner edge of the aileron -- gives much better resolution in light when you struggle to see the colurs]

The other approach to the rubbing areas near the root ribs is to put some clear book covering on the fuz just a bit bigger than the wing root -- provided there aren't any sharp, pointy bits sticking out the root of the wing this stopped the rubbing on mine very quickly (and I gather is what the IMAC guys do on C-ARF models -- as that is who put me on to it!).

Great to hear a few more of these flying, and the work on fuz reinforcement etc. paying off.

David

HI All,

After some deliberation I decided to jig the fuse such that the nose had 1 degree down thrust, then made zero lines for the stab (zero) and wing (0.25 degree) from my table. Everything is drying now and I feel that the results of this method came out pretty good. Used some home-made height gages, and everything looks spot-on while it is drying now.

Caution: I found two areas of caution, that are not intuitive: 1.), the aft pin of the horizontal stabs are not true, nor conisistent with each other. While the larger stab tube of both 1/2's were true, the aft pins of both stab 1/2's pointed "down" at some angle. Thus, not knowing this when I drilled the first perfect set of holes on the fuse, I had to adjust them downward and aft some (around 2-3 mm) to keep the stab 1/2s at zero degrees. Because of this, it was impossible to use "one" carbon pin to join both 1/2s, if I had wanted to, as they were intersecting each other at angles. 2.) The second concern totally stumped me for a few minutes. The aft aligment holes in the wing, while drilled "true", are not on the center of the rib!!!!!!!!!! When I first installed the wing, I had nearly 1 degree of NEGATIVE incidence, instead of 0.25 positive incidence. This took the majority of time to reposition and get perfect again.

With the wings finished and the cornes rounded, I found it difficult to find a congruent location to take alignment measurements from. I decided to measure from the fuse down the LE of the wing, until just before it started to make the radius. I made a small mark equal on both LE's. The "obvious" spot to use was the outboard corner of the ailerons, as they were factory cut I figured they would be "exact" to one another. However, after taking a bunch of different measurements, these were not the same on both sides, and again I settled on the LE position. Using this, the right wing tube hole needed just a smidgen of adjustment, to get equal measurements from these outboard LE marks to the top of the vertical fin. Also, this happened to "even-out" the little bit of wing -root that was not matching the fuse.

All-in-all, the alignment would have been 2/3rds faster had I taken the time to measure up the factory drilled holes. The plane looks really nice the garage, sitting with stabs and wings on!!!

One Question Please: Like everyone else, I'm considering how to mount the ailerons and elevator servo(s). The instructions show the "root" and "hatch" mounting methods. If you can cut a "hatch" in the skin, why hasn't anyone just mounted the elevator and ailerons servos upright, and in typical installations? With just a little enlargement of the servo horn slots, you can mount the servos vertically?????

Thanks for everyones posts!!
Jim W.

Jim,
You can mount the aileron servos more conventionally. I have seen the servo laid flat with a hatch etc. as well as vertically as you described. I went for a single servo and pushrod for the elevator because I didn't like two small seros at the back. Boring, I know, but it works :-)

E.

Hi Jim

Interesting findings with the anti-rotation pin indents on the fuselage. I encountered exactly the same problem with the main wing pins but not the stab pins! After I had installed the wing pins I also found the wing sitting at -1.5 degrees, if CARF can't put the indents in the right place why bother to put them there in the first place? Although these kits are on the face of things good value for money, I personally find these problems a pain in the jacksy and totally unacceptable. For the average modeller who would be buying this kit as their first serious pattern model having honed their skills on a more conventional type model, I'm concerned that if put together straight out of the box and un-adjusted for all the mistakes, their going to have a potentially poor performing aircraft. To spend the amount of time needed to complete this type of model not to mention the financial outlay, and end up with a poor performing aircraft, does nothing for the aspiring pattern pilot of the future or the manufacturers for that matter. Having said that, I wonder how many have done exactly that and had no problems verses others who have encountered a rather premature ending to their pleasure without realising why?! perhaps a poll to see how many Impacts are actually flying/amount of flights would be interesting to some.

Don't get me wrong, I'm not a "self appraised expert" or wish to imply any "self appraised expertism" just an aero-modeller for the past 17yrs! During this time I have designed and built a few models, the last being in 2000. The model was named 'Nouveau' you can see it at www.leicestermac.com ( please ignore the C*AP colour scheme ). I eventually came 2nd in Standard class (www.gbrcaa.org) with this model at the British National Championships 2000 flying against the eventual winner Simon Johnson who was flying a glass ship Sylpheed (anyone remember that one?) and coached by non other than Brandon Ransley!!!!!!
An achievement I'm proud of.

Keep it coming with the build thread, your doing a fantastic job!

Regards,

Andy.

p.s. I've never used an incidence meter so much

Jim/Andy etal.

In defence of C-ARF I have built a few pattern planes from other manufacturers and in all cases I am very glad I have gone back to first principles and established my own datum lines; and that includes some of the well known and more expensive European manufacturers. I have yet to find one that is right. The only exception was my Oxai Impression -- but that is much more more completed than the Impact -- but I would give it A+ for accuracy. C-ARF have (to date with the Impact) had a few problems with wind and stab tubes etc. I haven't seen in others (and I am sure they will get over).

But overall it is great we have competitive models in this price range, and a great community of modellers (and forums) to help build all our skills. What else would we do in deep winter?

David

I think that I expect an ARC or ARF to be off a bit. Maybe I'm a bit jaundiced these days, but after 52 years of building planes (I began when I was 4), I have rarely found a perfect model that came from a manufacturer.

Having said that I just built a Great planes Chipmunk with plug on stabs and 3 piece wing that was right on. My PINNACLE was beautifully-right! My IMPACTS were finished on the outside, straight, but needed a meter to set the wing and stab tubes. My BRIO has a straight wing and stab tube but needs a lot of finishing before it can be covered and painted.

The point being that it depends upon what you want, what you like, and what you worry about doing to a plane the most.

1. If it is alignment, be ready to do some work on an IMPACT.
2. If it is finishing get ready to get help or do the work on a BRIO!
3. If it is all of the above, get a PINNACLE and be ready to do some "stealth" work on your bank account... :-)

Regards,

Eric.

Hi
I found an almost completed plane, his name is Rhapsody.
I knew it when I saw a picture of that of the jason Shulman in world championships 2003 in Poland. I found this so beautiful plane for which I looked for by internet how to buy it, what I made at F3alorenz for 1165 euro.
http://www.f3alorenz.de/
There are many designs, it's painted in moulds (for white or blue or yellow color the cost is 999 euro). Wing's tube, carbon tubes of the stab are fitted. It's very easy to make it, only somes hours. The distance (alignment) between wings and stab, the incidences of wings and stab are perfected.
The plane fly straight ahead and there is no trim with the setup of origin of construction.
Stephane Carrier, a very good pilot (French team F3A with CPLR) tried it and told me it's a very good plane, that I saw when he did some figures of F3A international program.
The plane is so good that I buy another.
The Cocaine is also a very good plane built as the Rhapsody. It looks like the Impact.
claude

Maybe what the NSRCA needs to attract new pilots is a pattern plane called Cocaine, one flight and your hooked for life and spend every spare dime for more Cocaine.

You mean like this?

http://www.f3alorenz.homepage.t-onli...gfk.htm#cocain


/Erik