Hi folks any idea of possible ali servos for the impact. As the ali hole is pre cut and drilled.

I don't want to use JR. Also Jason seems to use 9151 rudder servo what other brands would fit in the wing.


Any feedback would be much appreciated.

Regards,

I ran with the Hitec 59XX servos. I have HS5975's on the ailerons -- but I think Hitec have discontinued them, so it would be back to the HS5925s for ailerons and elevator (I mounted in fuz, not in stabs). I used the HS5945 on rudder.

They fit in the pre-cut aileron servo holes. You just need to use slightly bigger screws, than the standard Hitec ones.

I went with JR8411s on rud and ailerons and JR3401s on elevator (again, mounted in fuselage not stabs!)

Have updated my Impact build thread showing the elevator servos installation - www.composite-arf.co.uk

Rgds,
Mark

Edit: DOH Just read you didn't want to use JR!

Hi Guy's,
I've just finished installing the rudder post and rudder on the Impact, what a horrible job[:'(]. I found setting the depth of the post a real nightmare to achieve a nice fit of the rudder. the problem was achieving the required throw without having a big gap down the hinge line, the rudder seemed to hit the side of the fuselage when deflected to the required 3" of throw, anyone else had this problem? I've settled for as small a gap as possible, which could only be achieved by setting the post at a slight angle to compensate for the change in thickness of the rudder thoughout it's length.
Still a value for money kit though, can't wait to fly it!

Servo's i'm using are:

Aieleron's - JR DS8401
Rudder - JR DS8401
Elevator's - JR DS3201
Throttle - JR DS811.

Radio is JR PCM9X with 2700 NiMh battery,
Power is YS 140LM and Hattori 693,
Fuel is Wildcat YS 20/20.

Bye for now,

Andy P.

I agree with you, it is very difficult to achieve a perfect result for the rudder hinging. In addition to this I found the composite rudder to be way too heavy (approx 70g). I am now building an open structure balsa rudder that will be hinged in the more traditional way.

Seems like I will save about 35-40g in the tail.

My fin is slightly offset to the left as mentioned in some other posts. However, I found that this could be corrected while gluing the tailpost.

gee,this plane sure made a big impact on this forum with so many posts

Model trimming is personal -- so make of the following what you may . . . .

15 flights in and I have set up that broadly feels comfortable for me. Still tidying expos. Tight but not overcontrolled. I found the settings in the manual almost 3D like -- so I am well back from there!

Model flying with OS140; standard pipe; elevator and rudder servos at back of canopy area in fuz; battery just in front of the wing tube.

This puts the CofG 20mm back from the front of the wing tube (about 2/3rds of the way back through it -- well in front of the suggested position). Locks onto a line nicely, snaps straight and controlled (see flight mode settings below), spins tidy. Only minor elevator needed for level inverted flight. 45 degree up, roll inverted test and it slowly drops its nose into a nice arc.

Motor and stab at 0 degrees incidence; wing at +0.25 degrees. Tracks down dead straight with only very minor mix of down elevator to low throttle. No mixing required for knife-edge. 2 degrees right thrust close but not quite enough -- so a touch of right rudder mixed to higher throttle (multi point mix used to get this right from about 1/2 throttle up)

Normal flight trim:
- Elevator: Up 11 deg; Down 13 deg (approx 14 and 16 mm respectively at fuz end)
- Aileron: Up 6 deg; Down 9 deg (approx 10 and 14 mm respectively at fuz end)
- Rudder: 30 deg (approx 55 mm)

Snap trim:
- Elevator: Up 16 deg; Down 18 deg (approx 19 and 22 mm respectively)
- Aileron: Up 9 deg; Down 13 deg (approx 13 and 18 mm respectievly)
- Rudder: 20 deg (approx 40 mm)

Less expo on down elevator than on up; quite a bit more aileron differential than in manual (30% on JR10X) to stop adverse rolling.

Necessary model maintenance -- round wing edges where they seat on fuz, and put some clear plastic (I used book covering) on fuz to minimise eating through paint!

Any other configurations out there working well -- partularly with CofG further back? I will experiment over time.

David

David,
Thank you for the wealth of information in your last post. I am printing it as I type this.

Regards,

Eric.

P.S. That wing pattern on your icon looks a bit familiar mate ???

Hi David,
Great feedback on set-up!
I'm nearing the proverbial light at the end of the tunnel and this really will help with my initial testing.
Keep up the R&D it's really appreciated.

Hi David,

Great write up.

Are you carrying any elevator trim with those settings.

Secondly,

Does the fuselage look as if it is flying at a good angle to the horizon?


Regards,

Peter

Hello everyone,
Great information on this thread.
I got my Impact about one month ago, and have been flying it for about one week now.
I will have a complete write up by next week with a bunch of pictures..... Meanwhile, I'm using the new Hitec HS-6975HB on the wings and ruder, and for the elevators I'm using Hitec HS-5245MG. The 6975HB are very fast and accurate. The plane is electric powered by the new NeuMotors 1515/2Y with a 6.7 box on a Diversity Model Aircraft 10S3P 6600MAH. This motor is so efficient that after a 10 minute flight the motor temperature is only at 115 degrees. Performance is amazing.

Regards,
Pedro

Peter,

Yes, at these settings it is carrying a little down trim (about 1mm elevator relative to stab). I should have included that bit -- well reminded!!

I have been doing a bit of work on wing versus motor incidence and I am pretty comfortable that the +0.25 wing relative to motor is right on the up/down test. Greater incidence on the wing and it (predictably) pulls to canopy on the up line, and opposite if wing is lower. Over the next few flights I will experiment with the CofG in case it makes a difference to trim -- my sense is it won't.

I am happy with it in flight -- but I would admit I haven't had a good hard 'judges' look in level flight. From recollection it didn't look to be flying either nose up or down on the flat bits (like the long inverted line from the cuban 8 to the stall turn in Expert/P05). And nobody laughed at it or complained at Doncaster on Sunday (always a good sign)!! Fuz also seems to sit straight through the rolls -- but I have been thinking more about rudder throw/expo when doing them.

So after a few more flights I will likely get to which is easier to fix -- move the stab anti-rotation pins a fraction, of change downthrust (and wing incidence).

And one more (potential) tip -- the combination of quite thin underacrriage legs where wheel bolts go through, and the rounded legs against the spats, create a risk that a clump of grass or something equivalent can get caught in the gap and tear the wheel bolt out of the leg - - which causes the plane to stop abruptly as the leg digs into the strip. Fortunately mine was almost stopped when I discovered this so damage was minor. I shortened the legs a fraction to get a more solid area for the wheel bolt, and put a fillet in to seal between leg and spat that grass cannot catch in (and recognised I hadn't thought of this before because Bolly legs/spats interlock so this can't happen)

And for those thinking about right thrust, I am using APC 17 x 12 prop.

David

Great minds think alike on colours -- Chip got the design right, but I prefer the red, blue and yellow!!

David

Actually Dave Guerin did mine :-)

Chip's design and Kirk Gray's colours :-)


Is there any origianl thought left :-)

Eric.

Pedro, Where did you get your motor/controller/gearbox, and batteries? You said DMA for the batteries but he doesn't list any lipo's on his web site. What gearbox and controller are you using? Did you get everything through DMA, or piecemeal from here and there? Is everything currently available to everyone, or did you get some pre-production stuff? Also, you said the motor was a 1515/2Y, and I don't see that motor listed on either DMA or Neu's web site.

Thanks,
Norm

I got everything from Steve Belknap at Flydma.com. The motor was a pre-production unit, but I believe they have it available right now. I checked the web site and it looks like the 1515/2Y-F is mislabeled as 1515/2D. I'll make sure that gets updated. The F stands for finned motor case. Let me know if you have any other question.

Regards,
Pedro.

Norm,

The batteries are also from FlyDma.com. These are new Lithium batteries that they just finished some performance tests on and are getting ready to be placed online. If you send steve an email, he will fill you in on pricing. They carry both 2200MAH and 2600MAH cells. I currently have a 10S3P of the 2200's and a 10S2P of the 2600's. They both have similar performance, but I like the weight savings of the 10S2P pack.

Regards,
Pedro

Any tips on how to put aileron servo in place[][]

I tape the servo lead to the body of the servo to keep it positioned roughly between the screws, then use the wire w/ extension attached and a stick to guide the servo into position. I made a long allen wrench extension using a dowel and a ball socket dowel wrench which was magnetized.

Put the servo arm on the servo and correctly align it prior to installing in the wing, raise the servo arm through the slot in the wing sking prior to screwing down the servo. Screw the servo down using the socket head servo screws that are available. Not to hard after you do it once.

Alternatly cut a hatch in the wing and cover the opening with tape and the cutout from the skin when the servo is in.

Thanks Brian!!

Trimming update -- had another 5 good flights and handed it to one of the trimming gurus for an opinion. I haven't measured it again since, but the changes were:
- For normal flight trim -- about 10% more aileron throw to tighten up response.
- For snaps -- about 5% less elevator, 5% more rudder, and 15-20% more aileron.

Experimented a bit with the CofG, and happy that the 2/3 way back through wing tube works well.

Still has about 1mm of downtrim on elevator, so I will now tidy up engine and wing incidence relative to stab -- probably by lowering the back or the stab a fraction.

David

Just wondering if anyone is using a bell crank on the elevator on the Impact? And if the answer is yes, how did you rig it so you could use the linkage for the rudder without the bell crank getting in the way?

Thanks in advance

Rob

Regards the IMPACT thread. A friend of mine recently built the IMPACT (without instructions since there were none at the time), and installed the adjustable stabilizer in his. On the maiden flight, the whole tail of the model nearly came off due to flutter. The whole stabilizer fluttered, and cracked the fuse circumferentially around the front of the fin. He throttled back and made it back safely but the damage to the fuse was quite severe. However the wings, stabs and rudder are all serviceable

I looked inside the broken fuse and saw that there was no reinforcement around the tail anywhere. He was lucky the whole tail did not come off in flight. A warning to everyone who will build an adjustable stab version of this plane. Fuse needs reinforcement in the aft end. I understand that there are factory instructions on-line now, and the aft reinforcement is spelled out. You should heed the warning and build it strong in the tail.

After considerable arguing with the factory reps, he just got a replacement fuse and he asked me to build the adjustable stab for him. I have just completed installation of the adjustable stab in the new fuse. It requires a tail post support block exactly 33.5 mm tall, under the tail post. The tail post was made vertical by using a 1/32" shim on the left side of front engine/chin cowl area.

The stab aligns at zero degrees with this 33.5 mm support block in place, and the front engine area supported as explained above. The bottom of the fuse must be in contact with the flat bench. I run my height gauge scriber along the fuse sides in the back, scribing the stab center lines, both sides. Table surface is plate glass and facilitates height gauge movement. Very light scratching was done to the fuse sides with the carbide scribe, and then the scratch was penciled in for visbility. Very thin, about the tickness of a human hair.

Inside the fuse, I supported the tail with a bulkhead in front of the fin, and a horizontal balsa brace from the bulkhead to the tail post. It was fitted to touch both fuse sides all the way to the tail post and to slightly bulge the fuse sides out to fit the stab perfectly. The carbon stab tube and 1/8" adjuster rod are epoxied to the brace.

The stab roots needed a little sanding to get proper triangulation. I am happy with the installation result.

BTW- the way I align the tail post center line with the stab centerline is through the use of a large 30" plexiglas isosceles triangle I made a long time ago specifically for this critical alignment. The triangle "height" is scribed in and is perpendicular to the large side or base. A series of parallel lines to the base are scribed onto the plastic with the back of a x-acto knife, and all scribed lines are penciled in. It makes perpendicular alignments a cinch and takes all the guesswork out.

The wing will be installed later. Wing alignment is easy once the stab and fin are aligned. Hope this helps some of you putting the IMPACT or any other model together

Matt Kebabjian

To all those who bought the white and Red Impact, -- are you going to to paint it and then put the rudder on or will you paint it with the rudder on?

I am going to install the rudder and paint it all together at the end. I dont think it will be and issue.


Peter