Bob Cotsford Posted August 15, 2017 Share Posted August 15, 2017 Colin, to make a 91 four stroke sound exactly like a Gipsy, replace the main bearing with a well worn and slightly rusty one. At least that worked for a second hand Magnum 91 Ibought second hand some years ago! replacing the bearings quietened things down and reduced the heat produced but it lost that scale tone Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted August 15, 2017 Author Share Posted August 15, 2017 Bob, you've inspired me. If I don't get the resonance I'm looking for from a secondary expansion chamber, I'll take the back of the crankcase off and chuck some sand inside, that should do it. (The motor is an OS62FV). Quote Link to comment Share on other sites More sharing options...
McG 6969 Posted August 15, 2017 Share Posted August 15, 2017 Make sure you use 'quality' sand, Colin. Apparently the white sand from the Rhine Valley is the finest one... Cheers Chris Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted August 15, 2017 Share Posted August 15, 2017 Colin I applaud your efforts to 'bury' the silencer and achieve a realistic exhaust note although you might need a pretty large can buried in the fuselage to get it deep enough. You still have the problem that with a single each beat will sound the same whereas the carburation of most Gipsy ensures each cylinder makes a slightly different tone. Quote Link to comment Share on other sites More sharing options...
Mike Etheridge 1 Posted August 15, 2017 Share Posted August 15, 2017 Went on a helicopter flight last Saturday from Redhill Airport over London and back. We waited at a cafe which is attached to an aircraft hanger which you had to enter to use the Unisex loo. Within the hanger were a number of interesting planes including two Chipmunks. I have forgotten what the blue biplane was?.As for the flight my first in a helicopter it was really excellent and I would recommend it.I am not sure about accommodation if it's required, but could the building I pictured be a 5 star hotel? Edited By Mike Etheridge 1 on 15/08/2017 20:33:31 Edited By Mike Etheridge 1 on 15/08/2017 20:35:22 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted August 15, 2017 Author Share Posted August 15, 2017 Chris, thank you, I'll nip over the channel in the morning and collect some Rhine sand. Simon, perfection is always beyond me! It will however sound more "Gypsy-ish" than an electric motor ever will! Mike, the biplane is a Spartan Arrow. I like the look of the hotel, very plush! Must stay there some time. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted August 21, 2017 Author Share Posted August 21, 2017 Since we got home last week I've spent time making up the secondary silencer, basing it on the article shown on the plan. I have used 20 swg brass. I thought it was coming along reasonably well until I ran out of silver solder. A visit to B&Q got me some brazing rod that I thought would finish the job. However I found this evening that the melting point of the brazing rod was considerably higher than the silver solder and the light gauge brass was distorting substantially under the sustained heat. It looks as if I need to scrap it and start again, which is a bit of a blow. Also I've proceeded with doping medium weight tissue on top of the lightweight silk on the wings. The method I used was to attach the tissue by doping it on around the edges only, then water shrinking it before applying a further coat of dope overall to adhere it to the silk. it has worked a treat. The result is a very tough and smooth covered surface. Covering this way is a slow and laborious process, but I don't want to use Solartex because I have seen too many beautifully finished and painted scale models. with the covering sagging in the sun. Although I'm not aiming for a concours finish, I don't like to see that. Sadly, I dropped the wing and it fell straight onto the centre section leading edge, pushing in the wing fixing dowels and damaged the blue foam fairing. Stupidly clumsy, that will take some care in fixing. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 23, 2020 Share Posted November 23, 2020 Glad that you put those pics of the fairings and the info about fitting them on there since I still have that hurdle to cross on my 1:5 scale version. Someone said that one of the G whatever number is completely wrong. I shall cut mine from scrap balsa before committing to the real thing. After much effort and several rethinks I now have the wing bolted in what I think is the correct place but would like to fit the tail using a laser meter since I do not trust my building that much. Since I do not have the flaps fitted I cannot use the meter without firstly covering the wing parts and gluing in those hinges, then of course I need to fit the wing tips first with the flaps/ ailerons correctly aligned.. Lousy plan and a devil to make from it. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 23, 2020 Author Share Posted November 23, 2020 Hi Martin, I’m pleased that helped. I got my Chipmunk to an advanced stage before I parked it in frustration, I had a number of issues with it but decided to build the Fury and come back to it later. Having said that I’m finding frustrations with that and I don’t think I’ll tackle any more Dennis Bryant designs. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 23, 2020 Share Posted November 23, 2020 Hi Colin, me too neither. Not as bad as my abandoned Dennis Taylor Mossie which even TN gave up on. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 23, 2020 Author Share Posted November 23, 2020 If you abandoned it Martin, it must have been especially difficult! Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 24, 2020 Share Posted November 24, 2020 One of the finest UK modellers (David Quartermaine) is blogging a BT Mossie build on RCSB if you are interested? DavidQ Mossie build Cheers Danny Edited By Danny Fenton on 24/11/2020 14:41:41 Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 24, 2020 Share Posted November 24, 2020 I meant Brian Taylor of course, not Dennis. Just do not even contemplate this thing. I could not pick up the light weight wing without my fingers going through the sheeting, and those complex bits of thin piano wire and tubing for the hinges etc would be lucky to survive one flight. The fus built in two halves split vertically down the centre turned into a banana. A friend actually completed one (the smaller version) including the u/c as shown on the plan and this collapsed on the first landing. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 24, 2020 Share Posted November 24, 2020 I agree that Brian's Mossie is very demanding, but plenty have built them successfully. But it isn't easy. I have all the balsa, glass, clear parts and even some Unitract retracts and was toying with doing it as a future masterclass....... Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 24, 2020 Share Posted November 24, 2020 I only bought the plan at a Nationals Traplet sale because the mouldings were expensive, thinking that I could make them myself. Little did I realise that there is not even a nacelle outline shown but I made some GRP ones and gave it all away to a club mate in the end. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 24, 2020 Author Share Posted November 24, 2020 I think I’d find that too much of a challenge! The priority now is to finish the Hawker Fury, which I’m confident about, then take a long hard look at the Chipmunk and decide if it’s worth finishing or not, it might be. Don’t think a Brian Taylor (or anyone else’s) Mosquito, much as I love it, would be my first choice for my next serious scale project. Probably something intrinsically slower might be more likely! My horizons will widen when I get my new workshop just in time for Christmas! Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 24, 2020 Share Posted November 24, 2020 It wont be a future Masterclass, I am pretty sure that there wont be any more. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 24, 2020 Author Share Posted November 24, 2020 After the effort you’ve put into it Danny that’s a shame but it must have taken a lot of your time, you’ve been unstinting in your support for everyone and I’m certainly grateful. The Chipmunk exposed my own limitations, I complicated it needlessly by experimenting with some different ideas and some aspects of the plan caught me out. I took on the Fury before resolving the remaining dilemmas with the Chipmunk and have taken far too long with that, also diverting limited time to other projects along the way has slowed that down. However I have at last got a lot more time now and I’m in the process of substantially improving my workshop and facilities, so am getting excited about being able to do so much more. Some of the issues with design detail and plan errors have been frustrating. The latest with the cabane wire detail on my Fury plan is a case in point, I’ve clearly got a plan on which I can now see the error has been identified but not corrected, it shouldn’t have been sold like that. However I’m sorting it out now. These projects invariably take time and some of us are slower than others. However models are now appearing and it looks as if we will see more completed Furies than Chipmunks. I don’t regret having a go at either in the Master Classes and I’ve certainly learned a lot in the process. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 24, 2020 Share Posted November 24, 2020 Hi Colin, thank you for that. I would like to see all the Chippy's and Fury's together one day think that would be ace. I also think it safe to say that the Masterclass has achieved everything we hoped. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Mike Bowman Posted January 8, 2021 Share Posted January 8, 2021 Can anyone help with Control throws for the Bryant chippy please. thanks in anticipation. Mike Quote Link to comment Share on other sites More sharing options...
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