Rich too Posted June 9, 2013 Share Posted June 9, 2013 I just got back from flying, it came to an abrupt end following a heavy landing, and the UC got ripped off (and it cost me a brand new 16 x 8 prop ) - oh well, time to modifiy the notorious Pulse 125 UC and move it forward - I will be using plastic bolts on all models in future!! Rich Edited By Dickster on 09/06/2013 15:50:02 Quote Link to comment Share on other sites More sharing options...
Simon B Posted June 9, 2013 Share Posted June 9, 2013 My pulse 40 used plastic bolts and it didn't stop the undercarriage ripping out, as they were an imperial size not far off an M6.... Quote Link to comment Share on other sites More sharing options...
Rich too Posted June 9, 2013 Author Share Posted June 9, 2013 Posted by Simon B on 09/06/2013 16:14:57: My pulse 40 used plastic bolts and it didn't stop the undercarriage ripping out, as they were an imperial size not far off an M6.... I think mine are M5's but there are also 5 of them which seems like overkill to me? I may try it with 3 - 2 at the front and 1 in the middle - or 4 max..Rich Quote Link to comment Share on other sites More sharing options...
Simon B Posted June 9, 2013 Share Posted June 9, 2013 It's been a while since I had mine, so I can't remember precisely Quote Link to comment Share on other sites More sharing options...
Greybeard Posted June 9, 2013 Share Posted June 9, 2013 Real men use steel. Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted June 9, 2013 Share Posted June 9, 2013 Funny had a conversation about this today at the field. The problem with plastic bolts is that they stretch and thus become loose. Thread lock is of little help. Apart from landing carefully (!), an undercarriage that is flexible should absorb most of the shock rather the undercarriage mounting plate. If the mounting plate is too strong, then a hard impact will take out the weakest point to what ever the plate is connected to. Si. Quote Link to comment Share on other sites More sharing options...
Rich too Posted June 10, 2013 Author Share Posted June 10, 2013 I'l try them and see how it goes. I must admit the std UC is rather stiff, and doesn't give at all - it did not bend..Rich Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted June 10, 2013 Share Posted June 10, 2013 Plastic bolts won't save your prop Rich......plastic bolts holding the U/C on will let go before the bottom of the model gets ripped out (hopefully) so the U/C comes away. Of course if you have spats these will usually punch two holes in your wing....& the prop still cops it!!! That said I always knock out the Tww nuts & fit larger plastic bolts to hold my U/C in place.....M5 in "up to 60" size & M6 above that....... Quote Link to comment Share on other sites More sharing options...
Bearair Posted June 10, 2013 Share Posted June 10, 2013 Its a good question and one that I often ask myself along with, why don't more trainers and intermediate model have the wings, tail and undercarraige held on with elastic bands?! Roger Quote Link to comment Share on other sites More sharing options...
will -0 Posted June 10, 2013 Share Posted June 10, 2013 Steel bolts otherwise they keep breaking. Quote Link to comment Share on other sites More sharing options...
Olly P Posted June 10, 2013 Share Posted June 10, 2013 Roger - Elastic bands are the future! I tend to use bands on 'trainer type' models, this incldes some of my more aerobatic/faster models which I use to try things out - if I do suffer an arrival, they can help take the sting out of it..... Quote Link to comment Share on other sites More sharing options...
Former Member Posted June 10, 2013 Share Posted June 10, 2013 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Roy Mundy Posted June 10, 2013 Share Posted June 10, 2013 I always use M6 plastic bolts for my undercarraige and they take a fairly hard landing with no problem, I found M5 kept shearing off. ..........................Of course 99% of my landings are greasers! I'm not sure it will save your prop but it will certainly save your fus being ripped apart! Quote Link to comment Share on other sites More sharing options...
Sparks Posted June 10, 2013 Share Posted June 10, 2013 On both my Wot4 and Acrowot Foamees, the first thing I did was to throw away the metal U/C retaining self tappers. Drilled and tapped M5 threads and used nylon bolts to hold the U/C. I've broken a few bolts due to heavy arrivals and wheels encountering pot holes. With over 300 flights clocked up between the planes the plastic U/C mounting platforms have remained in place. I commend this mod to the house! Edited By Sparks on 10/06/2013 16:20:39 Quote Link to comment Share on other sites More sharing options...
John Roberts 9 Posted June 10, 2013 Share Posted June 10, 2013 Posted by Sparks on 10/06/2013 16:19:33: On both my Wot4 and Acrowot Foamees, the first thing I did was to throw away the metal U/C retaining self tappers. Drilled and tapped M5 threads and used nylon bolts to hold the U/C. I've broken a few bolts due to heavy arrivals and wheels encountering pot holes. With over 300 flights clocked up between the planes the plastic U/C mounting platforms have remained in place. I commend this mod to the house! I did exactly the same mod on my foam Acro Wot although I use polypropylene bolts rather than nylon which I found to be a bit too strong. Highly recommended mod that takes only a few minutes to do. I have broken a few bolts with heavy landings which I am sure would otherwise have been enough to rip out the entire mounting plate. Edited By Sparks on 10/06/2013 16:20:39 Quote Link to comment Share on other sites More sharing options...
Erfolg Posted June 10, 2013 Share Posted June 10, 2013 Another way to go would be the use of 6BA or 2mm bolts/screws, and the minimum no off, say 3. Same idea as shear pins as used in some machinery. Quote Link to comment Share on other sites More sharing options...
Gordon Bushell Posted June 10, 2013 Share Posted June 10, 2013 I must be a bit light on undercarriage fixings on my Acrowot (balsa artf electrified) as it only has 2 off M4 nylon bolts. It still takes a fairly poor landing to remove the undercarriage, and to date the only fuselage damage has been dings from the undercarriage striking the bottom of the plane. Quote Link to comment Share on other sites More sharing options...
Rich too Posted June 10, 2013 Author Share Posted June 10, 2013 I'll live with a broken prop - thats enough though! Sounds worth doing then. I've started the repair tonight, and at present there are 5 M4's - I'm thinking of changing to 3 M5's in plastic - what does the forum think? Its a fairly large model.....cheers Rich Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.