Re: The Incomparable BTC-4

roddie Sat Sep 20, 2014 1:59 pm

Hey Mark... CONGRATULATIONS!!! Not every aero-modeler would/could conceive a design such as this.. "share" his idea.. document the build.. adapt the design for radial/beam mounts... balance both versions damn near perfectly... and follow-through with vids of the test flights. I think you did an AWESOME job on these airplanes... and they/you represent the very spirit of what this forum is all about! Thank you for a VERY enjoyable thread!

Theo Kleynhans Mon Sep 22, 2014 1:42 am

Hi Guys

Could someone please post the links to the 2 x videos.

I cannot view them the way they are posted.

Sorry for this.

Theo

roddie Mon Sep 22, 2014 2:36 am

Theo Kleynhans wrote:Hi Guys

Could someone please post the links to the 2 x videos.

I cannot view them the way they are posted.

Sorry for this.

Theo

Here you go Theo..

https://www.youtube.com/watch?v=ALFYNEkv050

https://www.youtube.com/watch?v=DwyEeEZgJdY

getback Mon Sep 22, 2014 1:38 pm

Good job!!! , Mark they were flying nicely , Hope you get the medallion straightened out it was wanting to scream Small Cox Logo

Getback

batjac Mon Sep 22, 2014 5:29 pm

Thanks for the compliments, Guys. I'll use the suggestions to try and get better runs. So, I'll move the tank closer, and see if I have a filter on my box. I'll cap the bottom vent and put an angled piece of fuel line on the top vent tube. The pics are deceiving, but the tank pick-up is actually inline with the hole in the Medallion venturi. I have some foam between the tank and fuse, and the strap and tank. I put it in after I took the picture on the previous page. If the changes don't work, I'll try doing a balloon tank.

The Low Down, Dirty, Deceiver Mark

roddie Mon Sep 22, 2014 7:17 pm

Mark, If you're gonna' move the tank forward on the BTC-4B.. why not try what I did to improve the draw on my speed model? You did state that the Medallion is a "thirsty" engine.. so when you shorten-up the fuel-line, try also replacing it with large size.. by using 1/4" O.D. alloy tube ferrule/sleeves on each end so it fits tightly on the tank and spray-bar nipples. It will be easier to install an in-line filter too, with the larger line. It's worth a try.. easy and quick too.

Here's some pics I'd previously posted.. of how I used the sleeves. You simply cut short lengths of 1/4" O.D. alloy tubing.. and "twist" the larger line into them until the line is flush with the end. This effectively compresses the lines I.D. down small enough to fit tightly on your fittings.

The Incomparable BTC-4 - Page 2 Lg_lin10

The Incomparable BTC-4 - Page 2 Lg_lin10

The Incomparable BTC-4 - Page 2 Lg_lin11

The Incomparable BTC-4 - Page 2 Lg_lin12

The Incomparable BTC-4 - Page 2 Lg_lin13

How many glow-head gaskets are you using on the Medallion? Do you think you might need to add any when running Sig 35?

Just some food for thought.. See Rusty's comments here..

https://www.coxengineforum.com/t3914-head-gaskets?highlight=head+gaskets

Theo Kleynhans Tue Sep 23, 2014 2:10 am

Great to see them fly Mark. Looks like you got it spot on!

Thanks for all the info and sharing. Nice to see.

Theo

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