Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Dec 09, 2011, 09:51 PM
Registered User
RknRusty's Avatar
United States, SC, Columbia
Joined May 2010
1,355 Posts
With the TD on the Stuntman chopper I have been using a 5.25x4 Top Flite nylon.
But on the Li'l Jumpin bean with a BW I use a 6x3 Cox. The Li'l Satan zooms with anything, but the loops are tighter with a 6x3 Cox.

I balance them on a home made tool. I stick a couple of single edged razor blades up parallel like rails and put a tight drill bit through the prop as an axle then lay it on the rails. Whichever way it rocks, I lighten.
RknRusty is offline Find More Posts by RknRusty
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 09, 2011, 10:04 PM
Registered User
RknRusty's Avatar
United States, SC, Columbia
Joined May 2010
1,355 Posts
Btw, I'm on my last Top Flite prop, so I'm cutting down some MA 6x3 and 6x4 props that I have. I do still have a TF 6x4, but I don't think I have a use for that.
RknRusty is offline Find More Posts by RknRusty
Reply With Quote
Old Dec 09, 2011, 10:25 PM
Registered User
Canada
Joined Nov 2000
6,944 Posts
Quote:
Originally Posted by earlwb View Post
The TF bylon prop tended to flex out to a smaller pitch at slower airspeeds and flex back to a higher pitch when the plane was going full speed down the straights.
Bingo! The rubber ducky blacks excel at exactly that.. Load them up in an abrupt manouver and the revs stay mostly constant.. Brilliant :-) One can also 'repitch ' the things by twisting the bejesus out of them just before launch for that inevitable last minute 'tweak'.
Order a few rubber Duckies (even the later nubby ones are good .. just not 'as' good as the originals) from Bernie. As bonus they are indestructible.
Oooh . DIY magnetic balancer: Buy a couple of nickel or quarter sized Neodym Magnets and a Wee finger balancer.
Stick the mags onto vise jaws and open the things up to fit the finger balancer so that only one end touches the magnet.
Bare is offline Find More Posts by Bare
Reply With Quote
Old Dec 09, 2011, 10:43 PM
Registered User
RknRusty's Avatar
United States, SC, Columbia
Joined May 2010
1,355 Posts
I'm up to my ears in 5x3 and 5x4 rubber duckies, no nubbies. Earlwb said he liked a 6x3 for aerobatics too, so at least I'm not a loner on that one. I'll keep switching and trying.

If it isn't too cold I'll fly this weekend. Can't wait for a taste of that hot fuel, I hope it comes tomorrow. But I still have some Sig 25 that needs a good filtering before I feed it to my freshly cleaned TD. I have an inline fuel filter ordered from the LHS but I don't have one on it right now.
RknRusty is offline Find More Posts by RknRusty
Reply With Quote
Old Dec 10, 2011, 10:54 PM
Registered User
RknRusty's Avatar
United States, SC, Columbia
Joined May 2010
1,355 Posts
Got my fresh fuel today, SIG 35%. I didn't have the great time testing it as I expected. It was 7:00 PM before I could get out to the workshop. I used last weekend's pressure bladder and cranked the TD and ran one rich run since I just devarnished and rebuilt it. Then I fired it up again full speed and it ran okay and noticeably faster than it did on the 25% SIG fuel. But after that, all it would do is sputter and flood over and over. So I tried a Bee head and it was worse. Tried more and less gaskets. Put the Gallbreath back on it and it tried harder, but I wasted 60cc of new fuel trying to crank it. I hate wasting fuel, so I gave up. I think using that old bladder must have been my problem, probably not enough pressure after being filled full so many times and sitting wet for a week. Come to think of it, it felt too easy to push fuel into it.

So I filled the Black Widow on my Jumpin' Bean and it cranked right up. It ran okay, nothing special, that's about it.

I'll make a new bladder and try the TD again tomorrow and I bet it'll run fine. That seriously cut into my flying time, I never got the chance to clean up the Stuntman, not to mention mounting the engine and making the new bladder. Now I have to do at least one more test run on the bench first.

I might just have to settle for flying the Bean or the Satan if I get to go at all. Oh well, them's the breaks. This hobby has its disappointing days.

EDIT Sunday: Nah, too cold, as well as a 15 mph wind. I for once didn't even want to fly. So I have all week to tune up. I always do better when I'm not rushed anyway.
RknRusty is offline Find More Posts by RknRusty
Last edited by RknRusty; Dec 11, 2011 at 07:59 PM.
Reply With Quote
Old Dec 11, 2011, 11:18 PM
Registered User
RknRusty's Avatar
United States, SC, Columbia
Joined May 2010
1,355 Posts
Quote:
Originally Posted by RknRusty View Post
...all it would do is sputter and flood over and over...I hate wasting fuel, so I gave up. I think using that old bladder must have been my problem, probably not enough pressure after being filled full so many times and sitting wet for a week.
I made a new bladder for it and it ran great. Now I can tell the difference in the hotter fuel, it screams. I can tell that tubing gets weaker every time I fill it up, so I'll start carrying plenty of spares in the flight box.
RknRusty is offline Find More Posts by RknRusty
Reply With Quote
Old Dec 12, 2011, 11:58 AM
Registered User
Canada
Joined Nov 2000
6,944 Posts
Great! Once graduating to this technique.. there's No going back :-)
DO use a tach. Dead silence in the middle of a 'move' can be expensive now that one has to pay 'collector' prices for cox bits.
Erm thinwall tubing comes in 100 foot rolls :-)
Bare is offline Find More Posts by Bare
Reply With Quote
Old Dec 13, 2011, 07:36 AM
Registered User
RknRusty's Avatar
United States, SC, Columbia
Joined May 2010
1,355 Posts
What's the best venturi bore for a pressurized fuel feed for my fun-flying? I know the one I have on it is larger than stock but not sure exactly how much it's bored. I tried to see what size drill bit will fit through it, but it's in between bit sizes.
I do have a screen on it, so that might change the bore requirement, but it's better for hunting gophers.
RknRusty is offline Find More Posts by RknRusty
Reply With Quote
Old Dec 27, 2011, 01:09 AM
Registered User
Canada
Joined Nov 2000
6,944 Posts
Going from memory ...and it's been a while
5/32 nd's IIRC was the usual rebore size for the TD venturi hole.
Best to get in there and gas flow everything in the carb as well.
I'm a believer in underpropping... max 'reliable' revs...for flat and level so there will be No sag in abrupt manouvers. Most of my flying involved abrupt gyrations 90% of the flight, so a wee bit of flat speed loss was the giveaway price of ful power when needed most.
Stunt type flying is of another species, likely even a 6x3 might work,TD's are mildly timed, no experiences with that tho.
Bare is offline Find More Posts by Bare
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Idea Pressurized fuel tank EricClark 1/2A Planes 17 Apr 22, 2009 07:09 PM
Discussion Pressurized tank 420TEE Fuel Plane Talk 10 Jun 26, 2006 10:42 PM
Pressurized fuel tank question.. IronKnees Fuel Plane Talk 14 Dec 20, 2005 06:04 PM
Fuel syringe for bladder tank Joe Ford Fuel Plane Talk 1 Jan 13, 2005 07:53 AM
Question correct hookup for pressurized fuel tank ricfoust Engines 4 Oct 15, 2003 08:39 AM