Steve Hargreaves - Moderator Posted May 23, 2014 Share Posted May 23, 2014 Bob I was thinking you could use either two 2V SLA cells or at a pinch two NiMH cells in series to power yer glowplugs..... Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted May 24, 2014 Author Share Posted May 24, 2014 I have enough trouble remembering to pack the basics when I go flying Steve without having unique items for one model to confuse me! Then I'd more than likely spend a fortune on plugs using the 'special' glow start on other engines... Anyway, the twin glow unit arrived from South Herts, just need to knock up a 4th switch - two * rx switches, one for the retract battery and now one to isolate the glow battery - don't things get complex on bigger models? The retract and glow switches are really just for storage use, when flying they'll get switched on when assembling the model and off when packing it away. The SH glow unit can use a 1.2 to 4.2 v supply, if the supply starts below 2.5v it assumes a nickel battery and shuts off at 0.8v, otherwise it assumes a Li battery and shuts down at 2.8v, with flashing LED indicating the battery type detected and low voltage warnings starting at 1 and 3v respectively. A very clever unit, but not cheap. In fact it's so clever I'm wondering whether I could rewire a 1600 2S1P LiFe or Lipo to 3200 1S2P as a supply. I might just take a suitable guinea-pig and soldering iron out to the garage to try. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 3, 2014 Author Share Posted June 3, 2014 1 off twin on-board glow drive from South Herts models, 2 off Perry-Conley VP20 pumps, 1 1800 2S1P LiPo converted to 1S2P and it's looks to be sorted. Fill tank, choke, switch on glow drive, back flick and it's running, needles alter the mixture just like needles should and it drains the tank in any attitude. At least there's no shortage of space for it all but it's a bit busier in the cowl The back of the tank to the carbs is 10" Edited By Bob Cotsford on 03/06/2014 15:26:45 Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 3, 2014 Share Posted June 3, 2014 Why is it still on the ground? Quote Link to comment Share on other sites More sharing options...
cymaz Posted June 3, 2014 Share Posted June 3, 2014 Well done There is nothing more frustrating than several little niggley problems. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 3, 2014 Author Share Posted June 3, 2014 Jon - shhhh! I was supposed to be working from home this afternoon! I did turn the laptop on and answer some email queries in between runs Fingers crossed for a decent day on Saturday for it's maiden. Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 4, 2014 Share Posted June 4, 2014 Sounds reasonable! Are you getting closer to the 9k you should be getting now? Once its run in give a 17x8 apc a go as the engine is so quiet and smooth with that prop. you should see 8000rpm on that prop. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 4, 2014 Share Posted June 4, 2014 Good luck for Saturday Bob, I think this is going to be a very impressive and what's more interesting aeroplane. I hope you can bring it to Greenacres. Edited By Colin Leighfield on 04/06/2014 09:37:29 Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 4, 2014 Author Share Posted June 4, 2014 Jon, for some reason my tacho seemed reluctant to work in the dull light yesterday, nasty cheap thing that it is. I need to get a decent one. It sounded right up in the 9k+ region, certainly way faster than previously. I was wondering about going to an 18*8 to help with the noise level as I do have a narrow APC one handy. Colin, yes, it's different. It's just a shame BH had to use that God-awful self adhesive vinyl covering. It's fine over sheet but it's really brittle over open areas between ribs in the wing. Of course if BH had just sheeted the whole wing it would have added about 2oz to the total weight but saved leaving vulnerable areas. An appearance at Greenacres depends on whether I feel confident with it by then, it's my first model of this sort of size. Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 4, 2014 Share Posted June 4, 2014 Bob, the 18x8 is likely to be too much, the 17x8 was excellent on mine and at low/medium revs you could hear the metallic ringing of the straight cut cam gears over the exhaust note. I really don't think you will have any trouble with noise. Be aware that this model will tip stall viciously so use a very gentle curved approach and don't try to hold the model up with the elevator, just let it fly on its own. I personally would suggest a very low elevator rate and no expo to make the model as precise as you can. Edited By Jon Harper on 04/06/2014 19:00:08 Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 5, 2014 Author Share Posted June 5, 2014 thanks for the warnings Jon! I take it you have owned one, were the flaps any help on landing? Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 5, 2014 Share Posted June 5, 2014 I have not owned one of these but have flown many models like this. I have also seen the video on the ripmax site where the bloke almost flips it on its back with his hamfisted approach. Flaps will help for sure as they will cause the wing root to stall first. As a general rule if you need to mix elevator with the flaps then you are flying too fast or do not have them down far enough. My La7 has very large flaps which pull the nose down slightly, I am able to control the decent using the power not the elevator. I then use elevator in the last foot or so to flair out. Whatever you do don't try and pull it in using a long flat approach with the nose high. I went though all of this in depth on another thread about a spitfire, people seemed to think it was helpful. the biggest mistake people make with warbirds is having the elevator movement like you would find on a sport model and this make the thing so twitchy they dumb it down with expo. This causes more problems. I would be surprised if more than 12mm elevator is needed up/down. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 5, 2014 Author Share Posted June 5, 2014 I've got around 50 degrees of flap available, that's about as much as the linkage will allow. On my Heine I find it needs some down mixing in as it pitches up regardless of speed. From the thread I found on RCU it doesn't appear to be bad for flicking, being quite a light machine for a warbird but I will still be avoiding sharp slow turns! Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 5, 2014 Share Posted June 5, 2014 Is that the hobby king Ki61? I had one of those but sold it to a friend. It was so light that it didn't really need flaps and did climb as you say. Most of the heftier warbirds wont climb with flap down 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.