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Grob 109 s

Posted: 26 Nov 2018, 17:02
by roo Hawkins
I have been looking at doing a grob for quite a while. After seeing that the old pj models kit has become available again on limited order. I was planning on ordering one but have decided to build a bigger one at 4.7 span and to fit a petrol engine. The pj one is 4.2 after speaking to Peter balcombe he as decided to order a pj kit so this may become a joint build thead when he gets his kit next week and finds time to start it. I started the plan last week and a week later it is glassed and I am now in the last stages of filling the fuz and the last bit of sanding . I will hopefully have it finished by next week. I will then start the wings. I will paint the fuz in the spring with my ash 31. How to build a fuselage in just over a week and lots faster than wood.

Re: Grob 109 s

Posted: 26 Nov 2018, 18:52
by Peter Balcombe
Well done Roo.
As you say, I have ordered one of the PJ Models 1/4 scale fuselage kits & plan to design a set of built up wings & tail feathers to make a 109B variant as used as the Vigilant T1 (recently axed as the RAF initial trainer).

I have heard of mutterings about PJ Models items in very old threads, but Catwok was happy with his recently acquired Chippie from the same stable. As Roo says, I hope to receive my fuselage parts this week, so will soon see.
I’m expecting to receive a fuselage set comprising a white gel coat fuselage & cowl, dash-panel, seats, wheel spats and canopy - all for £195.

At 1/4 scale, my model will have a span of 4.35m and is planned to be electric powered.

Re: Grob 109 s

Posted: 27 Nov 2018, 07:58
by matt
Good morning Peter, I have also received a complete DHC-1 kit myself in the past few weeks. The fuselage is white gel goat and chop strand mat / polyester construction while the wings and tail plane are white foam with balsa sheeting. Overall very similar to a Pat Teakle kit and very reasonably priced.

Best regards, Matt

Re: Grob 109 s

Posted: 27 Nov 2018, 13:54
by Peter Balcombe
My G109 fuselage kit arrived today & the contents are as expected & shown in the photo below.
As Mick says, the parts are probably in line with a Pat Teakle type short kit, so don't think high end German kits.
However, the quality of the parts is quite good for what you are paying - far less than European kits, and the parts look more than adequate.
If you want a super scale finish then you need to be prepared to cover the centre join lines etc & possibly paint the completed model, but I am more than happy with what I have.

Re: Grob 109 s

Posted: 27 Nov 2018, 15:38
by Martin G
Do PJ Models have a website?

Re: Grob 109 s

Posted: 27 Nov 2018, 18:11
by catwok
Hi chaps, I've got to know Pete quite well over the past few months through a mutual friend. He has asked me if I would do some low key advertising for his kits. As you have seen from previous posts, he is doing a Grob 109, 1/4 scale Chipmunk and a 1/4 scale ASK 18. All follow the same construction method.

If you would like anymore details or want to order anything, please PM me or call me on 07771 856362.

Paul

Re: Grob 109 s

Posted: 29 Nov 2018, 21:37
by Peter Balcombe
Comparing various measurements of the PJ Models fuselage with a couple of scaled 3-view drawings taken from the Internet (not necessarily accurate in themselves) indicates that although the fuselage is pretty close to 1/4 scale in its major dimensions, the wing root chord appears to have been ‘stretched’.
I would imagine that this has been done to give a lower wing loading as the model is said to have good flying characteristics.
The root section is something close to E207 and the full kit had I think a span of 170” (4.3m) which is just over 1/4 scale for the shorter span G109A (16.6m span).

I have scaled up the G109B variant (17.4m span) wing planform for the fuselage root chord, which gives a span of 4.8m. The alternative is to use the wider root chord with a 1/4 scale span (4.35m) :?

The target flying weight of the PJ Models kit is 14-16.5lbs, so I guess I’m going to need 1500w or so of urge from an electric power setup to RoG. Looks like a 8-10S LiPo pack to keep the current sensible.

Re: Grob 109 s

Posted: 30 Nov 2018, 15:08
by roo Hawkins
After talking to Peter my fuz has been worked out at just under 1/3 scale. This is because of using a bad 3 view so this is now going to be a big model at more than 5 meters.

Re: Grob 109 s

Posted: 01 Dec 2018, 16:46
by roo Hawkins
Primer filler finished. Using a new product upol reface. Whould not go through the spray gun. So I had to brush it on and sand. .also did the ash 31 as well.

Re: Grob 109 s

Posted: 21 Mar 2019, 14:18
by roo Hawkins
Wings are now cut and ready for glueing in spars and veneer only 1 1/12 hours work.

Re: Grob 109 s

Posted: 25 Mar 2019, 14:25
by roo Hawkins
The veneer is all finished . Can not believe the size of them.I am now planning to mothball this build for awhile to finish the Fox and later on to restart my ash 31 build. May be next year when I will get back to it ??????.

Re: Grob 109 s

Posted: 23 Dec 2019, 13:40
by roo Hawkins
The grob project has a bit more work done when not working on the ash 31.

Re: Grob 109 s

Posted: 24 Dec 2019, 13:43
by roo Hawkins
Wing joiners made last night. Ply carbon and steel mix

Re: Grob 109 s

Posted: 27 Apr 2020, 14:43
by roo Hawkins
Got the grob out of the loft. I have been doing 15 to 20 every couple of days in lock down.

Re: Grob 109 s

Posted: 28 Apr 2020, 20:18
by B Sharp
Roo, pardon my ignorance but what's with the joiners? Ply, carbon and steel???? Why the mix of materials?
Brian. :?: :?: :?:

Re: Grob 109 s

Posted: 29 Apr 2020, 07:51
by roo Hawkins
B Sharp wrote:
28 Apr 2020, 20:18
Roo, pardon my ignorance but what's with the joiners? Ply, carbon and steel???? Why the mix of materials?
Brian. :?: :?: :?:
It is to keep the weight down ply core with ud carbon and twill carbon the steel is for fixing points.

Re: Grob 109 s

Posted: 29 Apr 2020, 08:43
by B Sharp
Ahh. Ok Roo now I understand.
Brian :)