kiowawarrior2

Hi there guy's,
Was wondering if there is anyone out there who can help me out with a query I have about setting up my engine? It is an Irvine .40 ringed rear exhaust engine with a bolly fixed length tuned pipe. Now I need to take pressure from somewhere for the fuel tank but I am not sure where. In the instructions for the pipe it says to put a mac's thin-walled pressure nipple at the thickest section of the pipe. But that would make for a long pressure line to the tank. I believe that the backing plate can be drilled and tapped for a pressure nipple (this would be my preferred option) but I have heard that some engines aren't suitable for this set up because of the timing duration. The engine is brand-spanking new and I don't want to mess this one up.
Also, if there is anyone out there with experience with these beast's and their operation I would appreciate any advice that can be given.

Thanks from Oz
Thom

DHG

My Feedback: (7)

Thom,

Crankcase pressure was popular on the RIRE Formula 1 engines that used an open extractor, hence offered no other way to pressurize the tank. Pipe pressure is enough, and it's very user-friendly: Just hold your finger over the tailpipe while spinning the engine with the starter, and take your finger away as soon as it fires. Yes, you will need about 10 inches of fuel line between the pressure tap and the air pickup of the tank ... well worth it, not a problem! [8D]

Duane Gall
RCPRO

kiowawarrior2

Duane,
Thanks for the advice, Much appreciated. I guess I will have to get that fitting after all. Another question, what would the max rev range be? The instructions don't give any indication. They just make a few suggestions as to prop for different aplications. This engine is going into a S1D racer (standard 1 design fomula used here in Queensland Australia) and though this ship isn't going to be raced in that class I am looking forward to testing this combo out.

Cheers,
Thom

Ed Smith

Thom,

Be cautious about using the MACS pressure fitting. The flange Dia on the fitting is too small and will pull through the pipe wall as the outside nut is tightened. To fix the damage I used a 6-32 screw and drilled a small hole down it. I locked it in place with a nut on the outside and inside.

A preferable installation is to find somebody who has aluminum welding skills. Ask them to put a 1/2 dia x 1/4 thick blob of aluminum weld at the fitting position. then drill and tap through that. The fitting can then be locked from the outside. I found the best position was closer to the largest diameter of the pipe. Too close to the header and every one of my pipes broke right through the hole. From a pressure standpoint the fitting position is not that important.

Ed S

Terryoc

Thom the best way to put nipples into the carbon Bolly pipes that I have found is to glue in a piece of 1/8 aluminium tube with 24 hour or super strength araldite clean everything with acetone or thinners before glueing and put a small piece of glass cloth over the top of the nipple down onto the pipe to reinforce the glue and sit it out in the hotest sun possible until hard.
I have 21 size pylon pipes with this type of nipple and have had no trouble for over 5 years.
Hard to suggest a prop with out knowing which pipe you actually have it might need a lot of revs and might not it should have a number on the pipe to say which one it is . Dont expect it to be a lot faster to the other S1D planes about as I know that they almost have a maximum speed due to the thick wing .
Terry
Oh and to clean up your long pressure line just use a piece of alum tube or nyrod from the nipple to the front of the plane and cable tye it to the pipe

DHG

My Feedback: (7)

Thom,

You asked about the max revs. If it's a ringed engine, 20K will be your upper limit. Above that speed, ring flutter and the "diminishing returns" due to ring drag on the cylinder wall tend to rain on one's parade. I would suggest propping it for about 18K on the ground. The APC thick-hub Quickie 500 props (8.75 x 8.25, 8.75 x 8.5, 8.75 x 9.0, 8.8 x 8.75, 8.8 x 9.25) ought to be about right. Only potential complication is if the pipe is too short to tune up with that large of a prop, in which case you'll need to clip the diameter down or rig some kind of extension on the header.

D.

kiowawarrior2

Thanks for the help guys, i appreciate your time. I have solved the pressure nipple problem by drilling the pipe just in front of the thickest part and have used super-strength araldite and carbon-fibre to fix it in place and support it. I'll try and give the engine a short run in the next few days, but I'll need to get a few more props the LHS doesn't carry a large variety of props so I may just have to buy them from elsewhere(I'll only be using apc's for this engine as I use bolly clubmans for everything else. I do have a bolly carbon-fibre 10x6 but it is an absolute pain [:@] to try and ream the prop so it will fit the shaft. I think the 10x6 is probably a little large in diameter and a little fine in pitch. The manufacturer recommends a 10x6 for aerobatics, but the only aerobatics my S1D will do are fully unintentional I'll try and get a few 8" and 7" props to get the most out of this beast.