Airsail Chipmunk Kit limited re run.

[Martin Whybrow]

Finally! Did the ship have a navigation problem???? Glad to hear that they're here now, let's hope customs don't mess around for too long.

[Martin Harris - Moderator]

Posted by Colin Leighfield on 28/10/2014 16:52:14:

Interesting, I'll have a look at my DB plan when I get home. I don't recall a reference to wash-out in the books on the full-size I've got but again I'll look when I get back. It certainly makes sense on a tapered wing like this.

You got my curiosity going Colin and I've had a quick look around the 'net. It's not authoritive but I found the following statement:

Fortunately I made some friends at DeHavilland Canada in my previous career, so I happen to have some good documentation for it, including airfoils.

As far as I've investigated they were NACA 1415 at root and USA 35B at tips. But despite an extensive search I've been unable to find the NACA 1415 Coordinates.

That's because it was not a NACA 1415 at the root. It was a NACA 2412 at the root. The tip was a USA 35B, same as the airfoil for the Piper J-3 Cub. The NACA 2412 has a really benign stall, but still has a well defined stall break. The USA 35B has an even more gentle stall with almost no definable break. Between that, and the 2 degrees of washout, the ailerons never actually quit flying.

This might be borne out by the maintenance manual Page 70 which shows the use of purpose designed incidence boards at 2 locations along the wings - unfortunately no data other than the allowable mismatch but it's probably reasonable to guess from the wording that they are designed to lay a clinometer on them to show level - although I suspect their main purpose is to provide an accurate neutral point for the control surfaces.

Anyway, this manual does include quite a bit of data which would be useful for scale modelling and although you can't download it without paying a subscription, it's all browsable...

Edited By Martin Harris on 01/11/2014 02:04:27

[Colin Leighfield]

Thanks Martin, you've saved me the trouble and that's really useful. I'm definitely going to build it into my Dennis Bryant version, it won't be too difficult starting from scratch. When I get home I will take a good look at incidences on the plan and most likely I will increase the root incidence by 1 degree to offset the 2 degree wash-out, which will automatically reduce the mean incidence by 1degree. I've thought about the design anomaly in the flap dimensions, but will probably live with it, depending on how complicated it looks to correct it.

If I was designing this myself I would definitely use the scale wing sections. I think that although we consider Dennis Bryant to be one of our top scale modellers and I respect the man for being way better than I will ever be, he was prepared to make some compromises and the wing section is a good example of that, although I'm sure the originals would have been better, just a bit more complex to do. I don't understand though why he ignored the wash-out, but as we've said before there have been enough of these built to show it is probably ok without it.

[ZK BAP]

Right, we have some more info on the kits. They are going to now be trucked across to the importer this week. It has not been a glamorous journey for a machine that was designed to take the quickest route, but never less I am sure once they have been built will be right at home up in the sky where they belong. I am really happy they have made the trip half way round the world and some lucky people will get the chance to build and fly one of these magnificent aircraft. Will keep you all posted as soon as they have arrived at the importers place, and will go from there.

Cheers,

ZK BAP

MFNZ 11300

[Martin Whybrow]

Can't wait

[Stevo]

Blimey thats the most excited ive seen you all year, Martin!!

[Peter S B]

 

I have been following this topic with great interest as I am lucky to already have one which I finished last year. I hope all of you that will be getting one have the same pleasure of building it as I did. I have added a couple of photos from the kit to one of her first flight. If any one would be interested I could add all the photos of the build to the album I have just started.

 

Cheers

Peter

 

Edited By Peter S B on 10/11/2014 16:13:33

[Stevo]

Still awaiting pricing... meanwhile I'm musing over the engine... Saito or Laser 70? Something like 13x6" prop?

[ZK BAP]

Hi Peter. Great to see a kiwi registration on your chippie Welcome to the thread.

Stevo, I am currently running a 13x6 on my fs61ar. Plenty of grunt, sounds and flies very scale like. I have used a 12x6/8 which still went well, just a bit faster thats all. i will be putting a 14x6 maybe 8 on the other one currently being built, but it is going to have a fs91ar in it. Most of my engines are ASP, which have all been fine and very reliable. Glad to hear at least people are going four strokes and not those whining two bangers that just dont cut the mustard for scale sound lol. Hopefully pricing will not be too far away. I believe it is in the process for your VAT etc at the moment.

Regards

ZK BAP

MFNZ 11300

[Stevo]

I dont even own a two stroke... sounds a bit elitist..!

[Peter S B]

Posted by ZK BAP on 10/11/2014 19:35:17:

Hi Peter. Great to see a kiwi registration on your chippie Welcome to the thread.

Regards

ZK BAP

MFNZ 11300

Hi,

Thanks for the welcome.

I didn't know it was a Kiwi registration, thank you for informing me. A lucky find of the photos on line (attached) and I thought it would be different from the ones I have seen. She is powered by an OS 52 FS which seems to have enough power.

I will go through my photos of my build and upload them to my album.

Peter

[Peter S B]

Hi,

I have uploaded the photos to my album of the Chipmunk. Hope it spurs you all on when you receive your Kits, enjoy your build and flying her.

Peter

[ZK BAP]

Hi all, great news. The Chipmunk kits are now available for sale. The importer has a thread now which is here Airsail Kits now available where you can PM him to put you hands up for one. Remember these are very limited and only available through this site / forum! First in will be best dressed so don't delay if you want one of these great kiwi kits.

Thank you for all the support and encouragement in this wonderful idea of bringing back some good old favorites.

Cheers

ZK BAP

MFNZ 11300

[Stevo]

Not sure which Airsail thread to post this on!

IT'S HERE And what a lovely box of parts it is. Even better it arrived when SWMBO was out making the transition from front porch to garage quite painless.

Couple of things!
I will fit flaps as advised. The instructions state one mini servo for the flaps, but I'm not a great fan of bell cranks etc., so, best to fit two... that makes for a four servo wing of course. So without wishing to add extra weight, could I make all four of them mini servos in the wing?As long as they are fairly decent ones metal geared and all that. I don't intend to do 3D with it. Not intentionally, anyway.

Power plant is Saito 72. fortunately or otherwise, I have no muffler for it. What would anyone advise here? I'm not adverse to brazing something up in due course.

Won't start for a while, no hurry. I just look at the box and drool.

[ZK BAP]

Woohoo Stevo bet you are a happy bloke! Plenty to feast the eyes on in the box then.

Flaps yes, totally agree. Servo's many ways. I too am not a fan of bell cranks and on the first one I built I used flexible snakes running from the center section to the flaps and ailerons using only two standard servo's. How ever on the second one I had opted for individual servo's for each aileron and flap and managed to get standard servo's sitting on their side for each with direct drive. They were mounted on ply plates bolted straight to the corresponding rib bay required for each surface. By using standard nylon geared units help keep the weight down as they are strong enough even when running a 91 FS up front as they only have to deal with one surface. This was the chosen setup after the first chippie which at the time I only had a DX5e, but now with a DX7s and DX18 the programming capabilities allow for more control and adjustments of more servo's and direct drive eliminates any slop in control surfaces. I will use the same set up on the current one that I am building now for the sake of an extra servo I have piece of mind, plus the fact that a 120 FS will be the ponies. I think if you fly it under normal flight the little metal geared ones should be fine. My original has one standard for ailerons and one for flaps ( futaba nylon 3003 i think ) and have been in good service for over 3 years with no problems, even tho I do throw it around a bit ( 61FS up front )

Regards

ZK BAP

MF 11300

[Andrew Price 2]

Hi Steve, Mine has also arrived, safe and sound. Wish I could wrap pressies as neatly!!

I'm excercising great restraint and will not open the box for looksee til next week.

[Braddock, VC]

I wonder if anyone building the airsail version could help.

I have one of the limited run and am deciding which engine to fit in it.

Questions I have are 1. did the model require noseweight.

2. is it possible to move the engine/tankbox rearwards.

I currently have a choice of several engines, all 4 strokes os 40 surpass, saito 62 and 82, laser 70 and laser 80.

I would like to use the laser 80 but it's a very heavy old beast and too long to mount where the plan shows the engine box fitted.

Many thanks in advance.

[Stevo]

Yes the comments on nose weight would be welcomed. For me a Saito 72 - yes that Saito 80 was a heavy beast!

Looking at the plans there is a fair bit of room in that engine bay, for a change.

[ZK BAP]

Hi Steve and Braddock, going by the chippies I have built so far, one with a fs61 and another with a fs91, the fs61 required the weight of about a single AA battery up front and the 91 none at all. In saying that it does depend on things like rx batt placement, ( try and get behind the tank, I run two 4.8v square packs side by side in both )servo placement ( right behind rx packs ) and how light you built the back end. All up she should not really be much more than 3kg, or even lighter if light coverings are used. The tank box can be shifted a wee bit to help with the engine install and balancing, and should be fitted last with engine mounted, tank in and cowl made up so all can be jiggled to get a good result. Even with a smaller engine, a wee bit of nose lead does not affect things too much, but if you keep things light you should be fine. I have even used foam tail wheels to help the back end with good results. The only downside is that the tail can bounce around a bit on taxi if the ground is rough, but you just have to taxi holding up elevator to force the back end down and go slow, otherwise no real problems. A 60 to 70 will be ample even a 40 will fly it ok, but as I have always said, you can never have enough horse power, so with in reason, the bigger should be the go in my opinion. My one with the 61 FS in it weighs in just under 3kg if that helps, unfortunately I have not weighed the one with the 91 FS in it so can't give you that weight. Both fly very nicely indeed, with the bigger one having more grunt to throw around.

Hope this is of some help.

Cheers

ZK BAP

MFNZ 11300

[Braddock, VC]

Thanks, ZK.

[Stevo]

Workboard duly re-papered this morning in readiness. Garage cleared next weekend and any shortfalls in consumables such as scalpel blades, beer, glue, cigars, beer, spare stock just in case, beer, adhesives and so on identified. Did I mention beer?

On my to-get list:-

1. Nav lights (maybe BrainCube)
2. Engine mount (any recommendations for an anti-vibration mount?)
3. Wheels
4. Tank (SLEC Yellow or Orange most likely
5. Servos (Those mini ones are an arm and a leg!)
6. Pilots (recommendations?)

Think that's about it!

[Trevor Rushton]

Steve and Braddock, I built one about 4 years ago; it was my first proper build after a long gap. I used an OS 52 alpha and added about 75 g lead to the nose. Performance was not sparkling but once it was up it flew well enough. I added flaps and they made landing much easier.

Following a stall on takeoff I stripped most of the old glass covering and re did it with glass and interior varnish. I have put my Saito 72 fs in but I have not flown it in this configuration yet. I have halved the noseweight now.

I have one of the new kits but won't be building it just yet; too many in the pipeline already!

[Pete B]

You haven't got beer on your list.....

Pete

[Braddock, VC]

I'm just putting all the equipment together in preparation, 4 mini digital servos each with 3 kg/cm for ailerons and flaps. I have some supertec mg minis that have 5.5kg/cm torque that'll do for the R &E and a futaba mini digital that'll cope with the throttle, saving a little weight as well. I have an 1100mAh LiFe battery for the receiver which will be a futaba fasst 2.4 one.

It looks like I'll use the laser 70 as opposed to the laser 80 as it's some 4 ounces lighter. This is handy as the tank can be that much smaller thus saving nearly 8 oz at take off. I have a 13.5x7 bolly which will do nicely if I can get the weight down to the design weight.

Got some nice 3" wheels and have to decide what colour scheme I want. I'll probably go with doped on tissue all over and cover over the top of it on the wings with sig Koverall sealed with poly C..

At this moment in time I've no intention of adding masses of detail, just happy with the scale-like outline and colour scheme.

Hope to start building early in the new year when I should have a dedicated space for building, either a shed or a loft conversion, whichever is the cheaper.

[Andrew Price 2]

Steve, Re beers.

Don't take chances with risky last minute purchases. Research to be sure you know which beers may be available, Ascertain the ideal drinking temperatures. You must also check the carrying capacity of the hanger fridge. Before you start building a thing - test beers thoroughly!!

Andy.