Seagull 80" DH Chipmunk

[Danny Fenton]

Lol its probably me confusing everything.

Chris went the 6S 5000 route, he wanted a bit more urge than mine on 5S 5000. we have the same motors and prop I believe?

5S with a 500kV motor. The 4258. this motor can give around 1200 watts, depending on how you prop it. 900 - 1kW will do me, I think a 15 x 10 should do it.

Not sure what Chris ended up on with his on 6S.

Mine on 5S, its enough for me

Build thread:

Cheers

Danny

 

Edited By Danny Fenton on 12/06/2020 11:31:54

[Martin Gilbert 1]

Thanks very much for the advice, Danny and Chris.

[Chris Bott - Moderator]

Here's a typical 6 minute flight on 6S, using 1357mAh. Peak power read 1121W

[George P.]

Mine is on a 360kv motor and 6s 5000ma lipo. On a 17x10 APC I get 1378 watts at 60 amps as tested on the ground. I set my timer for eight minutes and land with about 30% left in the lipo. Scale flying at around half throttle. It weighs 10.75lbs and so around 128 watts per lb.

I have been used to flying a 3d model with 220 watts per lb and so although I am sure the APC 17x8 I tried on the ground would be good at 1215 watts and 51.78 amps, at the moment I prefer the little extra power for some manoeuvres; although if I ever get flying again I will try the 17x8 to compare.

 

Edited By George P. on 12/06/2020 12:57:10

Edited By George P. on 12/06/2020 12:58:27

[Martin Gilbert 1]

Thanks for all the info, Danny, Chris and George.

[Anthony Scott 2]

I have recently acquired an Army camo version which I intend to power with a glow motor. Does anyone know if the finish is fuel proof?

TIA

Tony

[George P.]

They are covered in Oracover and so fuel proof.

It was always my practice to add fuel proofer to the bulkhead/ tank area when I used to fly i.c. in an artf. However, a.r.t.f.s have improved considerably since then and I believe the bulkhead is already proofed. Worth checking over and proofing yourself if you feel it needs it.

[Anthony Scott 2]

I was curious about the painted cowling but safer than sorry as you say.

[ARC]

did or does anyone experience cooling issues with there chippy , will be running a petrol in mine but unsure if the front opening is enough and what about the air out , any thoughts /options

[Vince Findlay]

Hi ARC, My thoughts were the same as yours when looking at the cowl inlet, especially because my engine (Laser 180 4 stroke ) had only been bench ran a couple of times. I've read a few times before that the inlet area can be a lot smaller than the outlet and I could have used a baffle but the Laser takes up most of the cowl depth so I opened up the front quite a bit...Far from scale! (you don't notice in flight) I cut out most of the bottom of the cowl and have a curved aluminium baffle behind the engine to help the air to exit...I also reinforced the firewall area with carbon tows and epoxy.

I know the model is way over powered with the Laser 180 and a 100 or 120 would be more like it! But the Chipmunk flys great and is ideal for running in the engine...Flys on a fast tick over and goes vertical with a 18 x 10 Prop...

Vincehttps://youtu.be/vrsjHoO-SVU

[ARC]

Hi Vince ,

Thanks for the info. My Saito 21 is a snug fit, can work the baffle so its enclosed and route a hose down the bulkhead and out , I think opening up the nose is a good idea even if its only a small amount and where my exhaust hose pokes through the bottom of the cowl I will open that up as well to ensure a good flow in and around the engine.

Like you say from the the ground and at a distance its still a chippy even with all the surgery

[Vince Findlay]

Hi ARC, The Saito 21 Petrol should be ideal for the Chippy. On hindsight on the inlet I could have just deepened the original inlet a bit and had a curved baffle from the inlet around to the cylinder head and barrel. Also on the bottom left the cylinder head covered and the same baffle and outlet at the rear....I just didn't want to cook my new engine.

I really like flying the Chipmunk, I didn't need any added nose weight to balance it, It's nice and aerobatic and also can be flown slowly. It's the only model I've ever flown that hasn't needed any elevator mixed in when applying full flaps for landing.

All the best with your Chippy and maiden.

Vince

[Ady Hayward]

Hi Folks,

Just "Chipping" in with my Seagull Chippy. It was an all yellow version but I found the port wing had Wash-in which is quite undesirable. I had to remove the covering to remedy the warp so decided to strip it off and re-cover in Oratex to represent the Chippie I first flew back in the late 1960's at 8 AEF RAF Shawbury. The oleo fairings were replaced by ones I re-worked and 3d printed. Not great, but look a little more like they should. Power is via a Laser 155 which will have a closely baffled cooling system and if possible a more scale like exhaust outlet. I have still to do a bit more detail such as wing walks and other markings but getting there.

Port wing underside showing the wash-in.

Dayglow Oratrim and home made stencilled markings

Adorned with vinyl coloured markings

Edited By Ady Hayward on 25/08/2020 13:41:59

[Danny Fenton]

That looks great Ady, much better than the camo or Yellow ones. I had mused about changing mine to silver, but it is what it is......

Cheers

Danny

[Ady Hayward]

Many thanks Danny.

All being well she will be followed by a 1/4 scale one for F4C/H. I really like the 8 AEF colour scheme so if sufficient documentation can be found is the way it will go.

Cheers

Adrian

[Danny Fenton]

Funnily enough..... I have also started a 1/4 scale Chippy for F4C. We may be inundated with them .

I am doing WP788 based at Sleap and have got access I like my silver and yellow ones.

Just drawing my own 5 view as all the available ones are rubbish when compared to photos.

Cheers

Danny

[George P.]

That's a great scheme, Ady. Well done. sir.

I had thoughts of changing the scheme on mine but I do like the yellow in the air. I haven't flown mine this year, yet.

A 1/4 scale would be nice I bet.

[Martin Gilbert 1]

That is a beautiful looking scheme, Adrian.

Which Oratex silver / grey did you use, please?

[Ady Hayward]

Many thanks for the kind words Folks.

The tailplane, elevators and rudder were rebuilt along the same lines as Danny's Chippy with the finished with all parts together weighing just a little more than the original tailplane on its own. (Liteply structure...Not!). I do wonder at the ply structures Seagull use at the back, especially the liteply skins. The Chippy is still in build as I am trying to get closely fitting baffles around the Laser engine which may enable use of a scale like exhaust if I can separate the hot areas from the carburettor. I was going to go to town on the flaps and ailerons but the structure of the wing trailing edge made the task way OTT so left it as-is

[Ady Hayward]

Hi Martin, She is covered in Oratex light grey and the cowl is Oracolour light grey. The oracolour was supposed to match the film exactly but is quite a bit off the mark. It is not very close to the "Light Aircraft grey" used by the RAF, but the closest there is apart from a complete re-spray. Decals are vinyl and the dayglow is oratrim. Serials are airbrushed acrylic using home made stencils.

[Martin Gilbert 1]

Thanks for the details, Adrian. It's a very smart c/s.

[Martin Gilbert 1]

I notice that the small air intake scoops on each side of the cowling do not seem to have been opened up by anyone on their completed model. Is then the large opening at the front end of the cowling sufficient to provide cooling air for the esc etc.? I presume so - just checking.

[George P.]

Posted by Martin Gilbert 1 on 30/10/2020 09:30:59:

I notice that the small air intake scoops on each side of the cowling do not seem to have been opened up by anyone on their completed model. Is then the large opening at the front end of the cowling sufficient to provide cooling air for the esc etc.? I presume so - just checking.

I have had no problems at all just using the inlet at the front end of the cowl. I have placed the esc at the bottom of the bulkhead so that the air travels over this before exiting through the gap between the bottom of the fuse and the bottom of the cowl.

[Martin Gilbert 1]

Thanks, George P.

[Ady Hayward]

Hi Folks,

I finally have my Chippy ready for her maiden. Has a new Laser 120 fitted instead of the Laser 155 so there is a little more space in the cowling for the baffles to surround the engine. All up weight is 5.3kg (11lb 13oz) so nearly 1 lb heavier than I wanted even with built up balsa tail feathers so I am somewhat bewildered how Seagull recommend a typical 4.8kg (10Lb 9.5 oz) auw on the box cover. No ballast is fitted and she balances out between forward and rear limits with an empty tank. With the original tail feathers she would have ended up closer to 5.75kg-6kg due to the extra nose-weight that would have been required. Still she is what she is and should fly OK at her weight. Engine runs were uneventful with no apparent overheating issues and sounds lovely with the stock exhaust and scale like exhaust. The last item to be done is to source a light weight pilot for the front seat.

Ady

Edited By Ady Hayward on 21/11/2020 20:12:11