If I recall properly, they are 2mm

Hi Andrew,

I replaced both grub screws with a single 2X56 machine screw that I ran all the way through the venture and case, and noted no difference on the tachometer readings after the mod! Only required chasing the threads first, with a 2X56 tap.

Is Jan Holuszko out of the Wasp C/L venturi business? He made an excellent venturi, and used the original AP needles, and spring to keep cost down.

Hope your workload lightens up soon my friend.

Bill

       I'm patiently waiting for test results. Mine didn't fair so well. I still have one NIB however. Ken

OK guys,
I have done the mods, turned up some delrin bushes and tapped them for the Cox 0.049 Tee Dee venturis. Using the Texas timers replacement for the TD NVAs, produces an excellent control line venturi assembly for the Wasps. The bushes turn out to be mighty thin. However the bush and Tee Dee venturi is held by two small grub screw which I have loctited in.
  The finished job looks quite neat, but not in the league of Jan's late lamented conversion. It works exceedingly well and I now have 5 Wasps converted in this way. They make great sports engines and behave just as the Norvel Big Mig 0.061. I don't suppose they would work too well with the way Ken thrashes his Wasps, but otherwise they do the job. With the modification costs and original purchase price, I would probably been better off buying the Norvel, but I had stupidly stocked up with Wasps, before I realised they had some shortcomings. They will do fine for grandsons to play with. if they break a Wasp, it is no big deal! I will try and photograph the set up if anyone else wishes to try it.

Regards,

Andrew.

Hello Ken,
I have managed a couple of flights on an old Mirablis and I must admit it went very well, without any problems. Obviously I have not used it flat out, but it is a much better proposition than a TD 0.049. Very easy adjustment (Texas Timer plug there!). Swinging a bigger prop than I should be using, (7x4 Graupner, really too big!). All in all a very worthwhile mod. Well better than leaving them on the shelf. So there is a line of engines that my grandsons can lawn dart without me worrying.
Seriously, I think the idea of a P/L swop for your damaged Norvel is not bad (assuming it is an 0.061). I am very impressed with the quality of the P/Ls. It is almost as if they were subcontracted to a really good company, the rest isn't too good, the shaft bearings were all over the place. Much worse than even my amateur bodging on a lathe! I sent at least 2 Wasps back as the main bearing fits were "worn out" before the engine had even been started.

Regards,

Andrew.