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Peter Jenkins

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Peter Jenkins last won the day on December 21 2021

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  1. As I mentioned above, at the December AGM of the GBRCAA, a motion was passed that completely changed the existing Clubman Schedule. I took the decision, therefore, to update the section in my book for the Clubman Schedule. As I had had a number of suggestions for improving the book, I took the opportunity of incorporating these suggestions. I also changed the Practice Routines chapter as it was no longer much use with the new Clubman and then took the opportunity of adding a description of how to fly the Intermediate Schedule as an Annex. A few pilots, who are more experienced at aerobatics, are now entering competitions at the Intermediate Schedule level, the next schedule after the Clubman. This has resulted in the book increasing in size from 136 pages to 189 pages. Unfortunately, this has pushed up the price but I hope you will think that Edition 2 is well worth the price. The book is available on Amazon (link) and in the UK, the price is £24.99 for the paperback and £8.99 for the Kindle version. I have had comments that the Kindle is not as good as the paperback as regards the diagrams so, please remember that. Looks like Amazon are offering next day delivery with Prime. Alternatively, you can buy the book from me for £15.49 plus p&p (£3 within the UK). I will have to wait until next week before I get any stock so if you would like to buy a copy from me, please send me a PM with your address and I'll send you an invoice with instructions on how to pay. If you have any comments on the book, please feel free to PM me.
  2. Also, different propellor makes have different performances despite the same diameter and pitch! APC are the best unless you go carbon fibre.
  3. Sounds good Jonathan. If the Gangster wants to spin right then just be led by it. There is no requirement to spin in a particular direction for the B or for competition. I've just re-propped my Gangster 75 with a 13x8 (it's got a ST 90 on Hanno pipe) but the aircraft is a bit on the heavy side primarily due to the wing! A built up wing to current F3A practice would make it soooo much lighter. Still, initial experience with the 13x8 is that its turning at 10,600 and it could go up by 100 rpm as it's just broken into 2 stroking. That's given it a very much better vertical performance than with the 14x10 that was recommended by a friend - that only reached 8,500 rpm so a gain of 2,000 rpm was pretty significant. I doubt it will be unlimited vertical but it will fly some quite large loops. Next thing is to check the noise it generates, which, in the air is fine and quieter than another model with an OS 60 on a pipe.
  4. Just know that the silver card version was the best. You can prop down to get rpm up provided noise is not an issue. I think max power is at around 15,000 rpm and then it's close to 1 bhp.
  5. I don't know Ace. I had a Mk 2 and then bought another and it was the Mk 3 with the natural metal finish carb and that was significantly more powerful than the Mk 2. Putting a throttle pipe, as in my picture above, cranked up the power once again. The Mk 3s are cracking engines as well as being pretty quiet with the standard Irvine silencer.
  6. It's the Irvine 53 Mk3 you want. It has a silver carb not a black one.
  7. I think the reduction in pitch helps also to get the revs up. Provided you are not likely to exceed the max power rpm then as you let the engine rev faster you get more power but at the expense of noise. Don't forget that the prop going fast generates quite a lot of noise. You lose out on speed as you drop the revs but it's like selecting a lower gear in a car and you can maintain speed on a steeper gradient.
  8. The Irvine 53 with standard silencer is usually pretty good at getting through the sound test. If you are getting a max of 10k rpm, I would aim to up the static rpm by using either a 12x5 or 11x6 prop and see how much more power that releases. The 53 has peak power at around 15k rpm I think but noise, usually prop, tends to be too much. That being said, I think my 53 on the throttle pipe and 11x9 prop revs at around 11k rpm static. I can fly that at one site as we have the rule that if it doesn't sound noisy that's OK. The other site requires a sound test and I had to prop it down to such an extent that the available power is no better than with the standard silencer.
  9. That's great progress Jonathan. If you ever feel you need a significant power uplift on the Irvine 53 then a throttle pipe, as shown in the photo below on my Irvine 53 will do that for you. The Wot 4 is not quite unlimited vertical performance but I can fly very large loops with it! The prop is an 11*9 as the 12*6 revs went to 13 k! That would be fine of course but a bit noisy. The red tape is self amalgamating tape and stops the throttle pipe canister from sounding tinny. Helps with noise reduction.
  10. In Dec 2021, at the GBRCAA AGM, the decision was taken to change the Clubman Schedule. This has many new manoeuvres as well as being slightly longer. I am now well on the way to publishing Edition 2 of my book that will cover not only the new Clubman Schedule but also the Intermediate Schedule since a few pilots have decided to use the Intermediate as the first competition schedule they wish to fly. I will post here when Edition 2 is available most probably by the end of January 2022.
  11. Silly me! I meant IAD Model Designs and not Prop Guy! Well spotted Steve!
  12. I got the last JMB canister from Prop Guy. You could try him to see if he can help. Link.
  13. All I can say is the aircraft will handle best at that point. It will be a combination of features that appeal to you. Stability, feel of the controls and handling. You will be able to tell when you get there. If you go too far then you will feel that so just come back to the sweet spot.
  14. Without wishing to hijack this thread, I would observe that: - there is a range of CG position for every aircraft and the position marked on the plan may not be the optimum. Adjusting CG position by small amounts will allow you to find the optimum position. - adjusting up/down thrust, as well as side thrust to make the aircraft less sensitive to throttle, as pointed out by Jonathan, will also make the aircraft more pleasant to fly. - mixing throttle to elevator, or rudder for that matter, doesn't always work better than making physical adjustments as above but is certainly quicker and easier to do.
  15. I now use Nordlock washers (link) under the heads of the bolt. Do not use another washer in between the bolt and the Nordlock. You need more torque to undo such an arrangement than when you tighten the bolt. Never had one come loose on 120 four strokes. If you mount the bolts from the side without access, you could use a metal plate to which to silver solder the bolt heads and glue the plate the bearer. Alternatively, for smaller sizes use a bolt with a slotted head and solder a piece of piano wire through both bolt heads to stop them rotating. That was how it used to be done in my early control line days!
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