Jump to content

Ed Kershaw

Members
  • Posts

    88
  • Joined

  • Last visited

    Never

Ed Kershaw's Achievements

0

Reputation

  1. Many thanks for all your thoughts. Fascinating article, Gonzo. Interestingly, I have now actually bought both a SS25BBD and a SS30BBD. Having bought the 30, I thought it was a bit heavier than I wanted it to be, so I bought the 25 (on no better information than it was a smaller engine so it might be lighter - info on Enya engines being very sparse and hard to find!). The odd thing is, the 25 has the same external dimensions as the 30, and its also heavier! So the 30 is larger bore and stroke, lighter version of the 25.
  2. Evening all, I was just wondering if anyone has any experience of Eyna diesels. I've just ordered a 30BB diesel from the Enya website on a bit of a flyer, for CL stunt, with not much in the way of specs given on the website. I am hoping it will pull a 35 class stunt model (Magician) round pretty well. Any views or experience gratefully received - props/rpm/weight etc?
  3. Many thanks i12fly and Stephen. I think it's going to be the Flair kit. It seems to be quite a light build and, judging by the customer photos on the Flair site, someone seems to have achieved a more representative shape to the mid wing centre section, so that should be achievable without too much trouble. I'll post some news/pics when I get going.
  4. Hi All, Having decided my next project is to be the popular Fokker dr1, not surprisingly there seems to be a lot of choice. I was wondering if anyone has any experience to bear? Choices seem to be: 1. Balsa USA 1/4 scale - I can't find much detailed info on this. I have found one build thread on rcscalebuilder, but the builder modified the kit extensively so I could not get a good appreciation of the original intention. 2. Flair 1/4 scale. Seems to be quite a nice straightforward build, but seems to miss some essential scale features, such as the cut out in the mid wing around the cockpit. Whilst I am not looking for detailed scale, this seems quite a radical and possibly unnecessary departure from the original outline. 3. Zirolli 1/4.4 scale. Looks quite a straightforward build but I have read that it can come out very heavy leading to fast (and unscale like) flight. Also, the nose looks long and the cowl doesn't look that scale - perhaps I'm mistaken. 4. Geln Torrance 1/4 scale. Seems to be a very detailed scale model - more detailed than I really want to take on for this project. My criteria are: Reasonably scale looks - I.e. General outline must be reasonably convincing. Needs to be light. I ran out of enthusiasm for heavy models years ago. Any views or other information most welcome. Many thanks. Ed
  5. Does anyone know if you can get fine pitch pinking scissors/shears, say, 15 to 20 teeth per inch?
  6. 1  Mode 1 2  Oxfordshire 3  Oxfordshire 4  Self taught on MacGregor Digimax 2 - hence mode 1 addict
  7. I put a bit of work into comparing motors in an effort to assess 'power to weight' and efficiency, including building a dynomometer (the results were published on this site some time ago).  I have several Axis ranging from 400 to 90 size, a few real cheapies and several Scorpions.   My conclusions were that, from a mechanical point of view, Axis are superior to anything else I've seen.  By this I mean general robustness (e.g. twin races at the 'business' end of all motors), build quality, fit and finish of components, quality of accessories and robustness of mounting system.  However, electromagnetically I think they are possibly a bit old fashioned now and lag behind others.   Take the 4120/18, for example.  Weight 320g; Dia 49.5mm; 515kV; Cost £94.50.  Max continuous output? - Axi do not state, but they do state max BURST current 55A for 60S, so I assume the max CONT current is probably around their stated max efficient current of 40A.  It may be safe to run continuously at 45A - probably not much more.  At 6S, this give max cont power of 945W.  Max power to weight -  2953W/kg.   I had a stator burn out on a 2 month old 4130/20.  Axi repaired it free of charge.   Compare this with the Scorpion 4020/12.  Weight 304g; Dia 49mm; 542kV; Cost £57.50.  Max CONT current 80A; Max CONT power 1500W.  Max power to weight 4934W/kg.   So, if, like me, you like building 'light', you can do better than Axi and spend less money too.   When I compared the efficiencies of Axi and Scorpion on the dyno, there was nothing to choose between the two.   With a Scorpion motor you also get the 2 year burn-out and defect guarantee, plus a 50% crash replacement offer - so they're obviously pretty confident.  It's Scorpion every time for me these days for motors (although their ESCs still seem a bit 'agricultural').
  8. That's a technical looking job, Tim.  Very state of the art!  I had a similar idea for my GP Stearman, but doing it the "old fashioned" way with a lipo 10s setup.  The CG did come out right on the nail, though, with no weight added (the kit calls for 18oz inside a plywood box on top of the OS120).  AUW a shade under 14 lbs.  I do like light aeroplanes!  I think there's a good chance it can work on a tiggy because there's so much room under the bonnet, and an equivalent outrunner is so small.  This is a modified Scorpion 4035-600 heli motor - rewound for 195kV.  It's only 435g and delivers over 2kW.  
  9. Many thanks again to all for the suggestions and comments.  Is 14/15 lbs a lot to expect from the Flair TM?  I was hoping that would be achievable with our Hutson version.  Light aeroplane do fly so much better.  I remember I did once see the Flair scale sprung u/c assy for one.  Lovely piece of hardware, but I remember thinking it seemed quite heavy.  Maybe I'll get a shock when ours gets assembled and weighed.   Well, the fuz and flying surfaces are coming along well on our Hutson version and it's time to bolt some metalwork in the front.  We made the decision this weekend to go for the Laser 180, so that'll be on order tomorrow.   The build has been quite interesting so far, with various kit related anomalies and frustrations, but I'll write something about that in another section.
  10. I've read build reviews where the builder says he used ammonia to soften balsa to bend it into tight radii.  Does anyone know how this is done and where to get the ammonia from?   Many thanks. Ed
  11. There is one other possibility.  Sometimes rxs don't like what they see from (poorly filtered) switching becs.  This one cost me a model.   Ever since then I have used the UBec from Gordon Tarling, which, although a bit pricey, seems steady as a rock.    
  12. Many thanks to all for the comments.  An update on where I've got to with this:   I spoke to Geoff at Laser engines who informed me that they actually make a Laser 180 that is pretty much ideal for 1/4 scale Moths - long stroke, torquey, not lightly built at 1200g, and reliable.  He advised strongly against petrol conversions to Lasers.  They have never tried it and don't intend to.  I asked why the 180 is not advertised on their website and was told that as they sell all they can make, they don't need to advertise it!   The Saito FG36 petrol is the other option (thanks for the steer, Bruce).  It is quite heavy, all up (1700g+), and quite expensive - more than twice the price of the Laser.  There are various forum discussions about problems with lubrication on these - I don't know if this is sorted out yet.  Of the two, this seems the higher risk option, although less smokey and cleaner (probably) if all goes well.   I think the Laser 180 is the way to go....   Arte and Marty, your electric set-up sounds impressive.  That will deliver about 2kW at the prop - about 2.7hp.  I should imagine you'll be able to stand your Moth on its tail at 130 W/lb.    
  13. Peter, a photo showing the problem would be helpful.   If I understand you correctly, you are proposing to pull the wing roots together with a toggle clamp rather than screw them to the sides of the upper cabin walls.  This would put the cabin under compression.  Is that OK?  If it is, why not use a turnbuckle?  Then your only difficulty is making a LH thread, which only involves a small investment of tools from Model Fixings.   Or have I misunderstood things?   Ed
×
×
  • Create New...