jlkonn

My Feedback: (1)

Here are the weights of my recently received Impact.
It was weighed on a food scale before any of the cutouts were made and with no accessories or subassemblies attached.
There may have been a few pieces of the masking tape still attached:
Weights are in grams-
Fuse only 736
Canopy 102
Chin 68
Rudder 88
R.stab 112
L.stab 113
R.wing 457
L.wing 463

JLK

tggilkey

Joe --

The hinge line sealing material weighs 3 grams per foot with the protective paper still attached. I weighed a strip of the paper (1 foot long) removed from earlier use and it wouldn't register...

Good Luck!
Tom

vellum2

My Feedback: (2)

Cool - Thats for the info Tom. I stripped a bunch of weight out of mine so I'm not worried about a few grams here or there anymore ;-)

vellum2

My Feedback: (2)

Whoa - I can type - What I meant to say was "Thanks" Ugh - too early..

vellum2

My Feedback: (2)

Well Northeast Sailplane has a wonderful website! thanks for the info Tom. I ordered the tape so hopefully my snaps will improve too. I spoke too soon earlier - Can you believe I missed just about every snap during the last contest! I swear I was hitting them all day long in practice... I hate when that happens! Doh.

Joe W.

flying martin

any one have an impact manual

f3a05

It used to be on the Comp-Arf website.If it's not still there,
I think I can email it to you--it's a pdf file,whatever that means.

iflyrctoo

The manual can be found here.

http://www.composite-arf.co.uk/ImpactTips.htm

Joe Dunnaway

Lt Oneman

Hey this is one big post here. I'm fixing to get a Composite ARF Yak55 and my question is Composite ARF.com the ony ones making the Composite ARF?

They are about the only site i can find. Any help would be great.

dapan

My Feedback: (2)

hi
my impact is 5100gr and i am thinknig to cansel the cf tunel to go at 5000gr can anyone tell me how importand is the tunnel for the plane?
thanks
dapan

F-4

Am building an Impact. Alignment giving me fits as I keep chasing fusalage hole alignment issues. Is this thread still alive???

John

tggilkey

Hi Jon --

As far as you and I are concerned it is! I'm building one also -- a second one. Is there a specific alignment question you have? I know some have said the holes worked and others that used them more as “suggestions.� I tended (with the first one) to use them as suggestions -- actually for the wing, only used the main spar tube holes. For the stab, I used both spar and anti-rotation pin holes -- but with adjustments as necessary. Prior to this decide whether you are going with incidence adjusters or the stock setup -- open the holes for what you will need. For the main spars for wing and stab make one side's holes a good fit for the socket material and don't mess with it -- the other side will be the floater for trammeling adjustments. Basically a good setup (which I gleaned from others in this thread) was this:

On a flat table (important), have the front bottom of the fuselage (no engine, no engine cowl) resting (just touching) the table. Yeah, the fuselage is round so it will have to be stabilized -- I used a fixture which had a base with 2 threaded uprights; a cross piece between the uprights whose height is adjustable by means of washers and wing nuts. The height is adjustable and because each side is adjustable independently the vertical fin angle relative to the table top can be adjusted also. Prop the tail up from the table 45mm; then adjust the fixture holding the nose such that the fuselage bottom (right at the joint where the engine cowl would be) just touches the table.

Mark the location of the support fixture cross piece on both the fuselage (both sides) and on the cross piece (for repeatability...); also make your support block just slightly wider than fuselage width at the tail -- you may need the real estate for setting/measuring incidences later on. I tacked the block to the bottom of the tail after bumping the setup off the block twice... and having to start over with the setup. Hence the marks and tack job...

Get the fuselage setup so the tail is propped up 45mm, the front of the fuselage minus engine cowl just touching the table and the fin vertical to the table.

Now you are ready to set the alignment of the wing relative to the fuselage. Assemble the wing panels on the tube (and fuselage) and adjust the other side (the “floater�) until aligned as viewed from the back and from the top. Make the wing tips equidistant from a point on the bottom of the fuselage (just in front of that 45mm block). Come up with something repeatable – I used a small (1/4� wide) metal tape measure – sacrificed it years ago for this purpose – drilled a pivot hole on the center of one end and held it to the center of the fuselage at the back with a #2 sheet metal screw. Either the hole gets covered by the tail wheel or filled when done. The tape doesn’t stretch like string and with consistent pressure applied doesn’t sag much. There are better methods but I haven’t taken the time to put them together. Check out Bob Noll’s Perfect Alignment series.

When doing this stage of the alignment keep the surfaces close to zero so your other measurements don’t get skewed. Judicious use of tape can help hold incidence on one side. Sometimes the tube and socket fit is enough. I set the initial incidences at 0 by measuring LE and TE the same distance out from the fuselage or in some cases by a line established on the fuselage (drawn on removable tape of course…). I think I used 1 turn of positive incidence on the Gator adjusters (with the adjusters at 6� centers from the tube). After adjusting the screws, check the TEdges for agreement and same for Ledges. Obviously the differences should be the same. I was quite pleased with the way the first one trimmed out.

Digest this and many of the postings in this now longer thread… Look for things from PeterP, MalcolmH, David Gibbs and some others like Eric Henderson. I borrowed liberally from them during my build. Their advice was sound.

Good luck with your build and feel free to either post more questions or PMail me.

Tom

Jeff Boyd 2

I have recently finished an Impact and it fly's great . . still have more trimming to do (I guess this is really an ongoing thing ).

It is the plain white / red version and was originally built (by someone else) for Electric. I converted it to glow, did some modifications and repainted it. It has OS140RX / Aeroslave CF pipe / Bolly gear and spats / JR and weighs 4.75kg (just under 10 1/2lbs).

Currently it is carrying a little down trim on the elevators which bothers me. I am playing with the wing adjusters, thust, and CG at the moment and it is getting better BUT if I built another, I would fit stab adjusters for sure. I am still considering performing some "surgery" and fitting them even now.

Anyhow . . great flying plane, for sure ! !

piroflip2

what can I say,,,,,,,,WOW!!!!!!!!!!!!!!!!!!!!!!!

tggilkey

Very nice looking plane, Jeff! It looks like you did the same thing to the rudder that I did and plan to do on the second I'm building. Did you build your own rudder? 10 1/2 lbs! I hope to get the second one down there... On the first one my CG seemed in a good spot -- right behind the wing tube (suspended on fishing line through holes in the tube donuts) wings off and canopy on. I notice the foam "crutch" is absent -- that could save some weight but with a YS in front I might lose the tail. Good job -- it looks great. What paint did you use?

Tom

PeterP

Hi Jeff,

Congratulations on the model. It looks great.

I have been flying my model for close to 3 years and it is still going strong with DZ160 power. When I test flew my model it trimmed out with a little down elevator and it felt very floaty in the wind. In my previous posts I mentioned the incidence changes I made as a result which I feel improved the model. The modele is quite sensitive to CG changes, I found the best compromise for CG was when it balanced on the rear of the tube with wings removed.

In your case I would add the adjusters because if you try to adjust your wing to remove your down trim you are going to screw up your thrust line. The inbuilt down thrust is marginal on this model and it needs a little more. I increased down thrust by adding more positive incidence on the wing and then reseting my stabs to remove any elevator trim. The other benefit to doing this was it raised the tail of the aircraft in level flight which makes the model present better with a more locked in feel. It also reduced my elevator to rudder mix to almost nothing. Couldn't be happier with the changes. Adding stab adjusters is not difficult in this model. The gator units available from Central Hobbies work well, if I recall correctly I remember posting some pictures in the build thread.

Good Luck,

Peter

tggilkey

I'm glad PeterP chimed in -- it corrects my "mis-remembering" (me and Roger Clemens...) about CG location. I was remembering the Temptation/Genesis -- the Impact should be as Peter says -- rear of wing tube. Hope I didn't mislead anyone.

Thanks,
Tom

F-4

Tom,

Thanks for your detailed response. Decided to post my response as I think my issues are significant. I did build a flat table and am using with threaded rod system as you described. Actually got the idea from a post on this thread. Do have Bob Noll's CD and use his methods.

Milled all fuse holes per manual. Established vertical and tightened fuse to board/jig. Started with the stab spar. Got it dead on, level and square to fuse. Epoxied fuse tube. Mistake #1. Put stabs on and measured. Way off. "Honed" stab fuse tube until stabs were square. Of course, lost tight spar fit. Filled void with epoxy. Stab is now not removable. OK, on to wing. Centered and leveled wing spar. Wing spar is now level to stab and 90 deg. to fuse long axis. Tacked wing spar tube. Slipped on wings and checked level, incidence and 90 deg. Wings were level BUT, incidence was a neg 2 deg. and difference between right and left wing tips to tail post was 1/2inch! Had to elongate anti-rotation holes 1/4" to get to positive incidence. Right wing was forward of left and there was a 5/32" gap between right wing trailing edge and fuse. After multiple rechecks of measurements, determined that the right wing tube was the problem...not where it needed to be. At this point frustration set in and I sent my last post.

After much thought, I decided to rework the spar holes to change the angle through the fuse. This moved the left side of spar forward and right side back. That should "square" the wings. Of course, I now have wing gaps to fix. After many fit, mark, remove and sand iterations, the fit is okay and wing tips to tail post measurements are the same. One more check and I will spot epoxy the fuse spar tube and, hopefully, move on.

I have read each and every post in this thread and can not recall any complaints about the major issues I have experienced. Don't know if my kit was that bad or my expectations are just not realistic.

John

Jeff Boyd 2

Thanks for the compliments guys . .

Tom,
1. No foam crutch = after I added the 8 strands of Carbon Tow (you can see running from the wing to the tailpost), it was SO noticably stiffer I thought adding anything else was just weight.
2. Yes the rudder is built up . . approx. 1/2 the weight of standard, however it has no counter-balance. I didn't like the standard hinge method and went for the double bevelled / hinged method.
3. Paint = Auto paint and clear is 2 pack - 2 coats . . as used for custom work. I didn't paint it ! a friend is an airbrush teacher and he owed me a favour ;-) I was worried about the weight and told him to "make it LIGHT". Anyway, the left wing had 17gms of paint added and the right 19gms . . not too bad (painted the tops only, and left the bottom plain red).


PeterP

Mine still has just a hint of down trim . . . and it was windy today (first comp of the year. Typical) and was a bit "floaty". Got another promo point though (85.5%. Percent required this year = 80%). One more point and I go to F3A . . hmmmmm . . might have to "throw" the next comp. I DON'T want to go to the Masters as an F3A newby []. PS. you should get a group of guys down to Shepparton this year . . It would be GREAT to see you there .

I think I will added the stab adjusters, like you say. Then I could put it back on the "board" and try your set-up. I need to get it a little more locked-in. It's not bad, but I know it could be better. Mine now balances on the rear of the tube (wings removed).
I have noticed how sensitive it is to thrust changes too. Just a little side thrust change made a lot of difference today.

I'll try to look through the build threads and see if I can find your stab adjuster post . . would be a help.

Cheers, JB