AeroTech Pitts Python 50cc

Could've got some fly time this morning apparently. With the intermittent rain causing me to stay indoors. I thought I would get on doing more jobs on the Python as far as I can get till bits come next week. Cut down two 3 mm control rods and threaded them. These were for the elevators. Created a new model on the DSX9, and inhibited all the switches for Aux 1 to 3. Then created some mixes, ELV and Aux1. AIL and AUX2. Temporarily connected up a RD 921 RX to centre elevator servos and adjusted rods to suit neutral surfaces. Aux 4 is ignition off.

Fitted the wing servos with their ball links and aligned the horns to suit. I now need to make up 4 off, 3mm control rods at 65mm to connect the ailerons up. The horns are temporarily lightly screwed down till the ZAP Med arrives next week. The area under the horns also needs the covering lifting away so the Med Zap can work.

What else can I do in the meantime? Dry fit the cowl to see what i am up against if anything.

Question for those in the know. The firewall is blank, ie; no centre hole and the carb mouth is about 20 mm from the wall. Is that enough gap for the carb to breathe or should I cut a hole?

re Carb intake - I think 20mm is marginal so why not cut the hole now because if it turns out the engine might benefit from a velocity stack in the future you already have room.

The firewall now has a 35mm hole. Did some temporary set-ups using a RD921 so I could set up the TX and see things working. Discovered a BNIB JR Powersafe RD922 online and it came on Tuesday. Wednesday I bound it to the TX. Plugged in my servos and verified direction of throws. Looking good. I am not sure where the Powersafe will be located although I have located the three satellite receivers. Positioning of the Powersafe, tank, dual batteries, etc can only be accomplished when all the bits are here. Temporarily fit the wings, prop, spinner and move the components around until the plane balances at CG. There is not much guidance on the "net" where stuff goes and the stories are largely back in the "old days" where they were using sub C cells and heavy stuff. The "manual" is quite lean and sparse of any really useful pictures.

As it was raining today I have glued and screwed the control horns as per the instructions. Adjusted the tail flying wires and locked them up. I will leave the rats nest of cabling until I know where things are going to be placed then tidy up. Just had an email from Ripmax regarding the elusive exhaust muffler. I was going to use the GT60 as I did with the CAP232. No stock anywhere in the UK until November. Then I got a tip from a model shop that Ripmax had a GT55 muffler in stock. Identical flange dimensions. After a short phone call to RipMax aka Slough RC it will be delivered tomorrow. Ruddy expensive exhaust but copies are made of too thin material) so had to go genuine. That's my budget for this month and next blown.:whistle: :whistle:

Diverting my attention for a while I took a look over my flying wings and checked all is well. There is every chance of some slope soaring in the very near future.

Looking good Phil, must be nice to have lots of room inside the fuselage. When it comes to silencing loud petrol two strokes, I read an article by Brian Winch in RCM+E some years ago, I don't remember exactly how it was done, but one of the things was to bond aluminium mesh on the inside of the silencer, opposite the exhaust, and binding the outside of the silencer with a heatproof rubbery sort of tape. I've emailed Brian on a couple of occasions, he's always most helpful and I think he'd probably be able to find the article for you.

There is always a compromise with exhausts between noise suppression, scavenging (the latter more discerning in two strokes) and power. The bog standard DLE muffler is bit of a bean can so I bought a lovely polished aluminium silencer on Ebay at a good price. But in use I personally thought it sounded worse but at least it looked good. So, swallowing the fact of wasted pennies I looked around for something decent that would fit. The OS stuff had good reviews so checking the dimensions I splashed out on the GT60 muffler. Fits perfectly and is of thick gauge ally and internal baffle suitable for the engine size. It now sits in the CAP232.

Silencers are a science in themselves.

Of course RipMax is now owned by Slough RC but anyway they said they could get it to me within two days. I paid top whack though. Coming Friday morning though.

Spent some more time on the Pitts today after sorting the CAP232 carb and idling issue (I think)

Cowl now drilled and T nuts installed so it can be fitted. Image shows temp fitment. Clears exhausts nicely and maybe just a little dremelling for the spark plug. May also have to cut a slot in the lower front of cowl so air can flow over the cylinder head. Unfortunately the air scoop underneath won't fit without serious hacking so pointless. Tank installed and plumbed in. These Extreme Flight tanks are superb. Waiting on some bits, aka kill switch, RX batteries now. Next job will be setting up the interplane struts and brackets.

After deciding that Cashmoor was going to be very difficult to access (2 hr long queues on A354) I went back to working on the Pitts. The RX batteries came today along with Opto Kill Switch and little bags of 3mm machine screws and rubber-backed washers. Installed fuel filler, illuminated power switch and Opto Kill Switch and LED. Tidied up the interior after deciding that the Power distribution has only one place to go. The open space in the floor is to allow access to the lower wing bolts.

Then had to pull out the tank again to again to access the strut bolts and re-tighten.

If it is staying dry tomorrow I will get the Pitts out in the drive so I can dry fit wings and see how much weight and where is needed to balance it. I am hoping the two lipo packs will do the job but I have a feeling I may have make up a battery tray that sits over the tank. We will see!

Yes Dave B. It is finally out of the box after 4 years.:whistle: Hope your engine is still good too. Been in the carrier bag for three an half. :lol:

Wing Tube Mod. Anyone got some 4mm x 10mm RivNuts? I could get some from RS but only in 100s in a bag. :blink: I need probably 8.

Phil Ford wrote: Anyone got some 4mm x 10mm RivNuts? I could get some from RS but only in 100s in a bag. :blink: I need probably 8.

I got some rivnuts from Kays Fasteners earlier this year. Ten in stainless will set you back less than £3.00 and it's free shipping. Mine arrived in about 2 days

RIVNUTS

Thanks Mike. Found Kays on Ebay. Ordered a pack of 4mm Rivnuts and also a pack of type D threaded inserts in 4mm. This gives me a choice on how the upper wings and wing tube are secured with minimal screwing, etc. Total cost £5.95.