Slowly setting up to build a Bridi Escape.
 

After I finish my Super Kaos of course! [8D]

How to set up my Super Tigre SERIE X RE .61...

I received my header from Rossi. Great news!!!! The fit is identical to the stock header!

Now I have to learn how to set this bad boy up!

I believe there should be a silicone insert between the exhaust and the inlet of the header. Wow, it needs to be thin! Where do I get this and what size do I need OR-

Should I just use RTV Silicone?

I actually think this works! I can't wait to fire it up. I plan to route the exhaust down through the bottom of the fuse as Bill Cunningham did with his. As I understand, this should keep the warm exhaust blast off of the vertical and cause issues.

Then...

Do I tap the pressure nipple on the pipe as suggested by the mfg?

I plan NOT to set this engine up for maximum RPM, rather, I plan to set this engine up for maximum performance as shown in Dean Pappas's article on tuning a tuned pipe.

See here:

RE: Slowly setting up to build a Bridi Escape.
 

How could I forget the pictures????

RE: Slowly setting up to build a Bridi Escape.
 

A few more pictures.

It seems as though this will work wonderfully. I'll have to butcher up the front of the canopy a little to fit the header, but I think it will have to be. We are limited on options for these things nowadays.

I also posted a pic of Bill Cunningham's Escape. If you look closely, you will see the exhaust diverted through the fuse and exiting underneath.

Brian

RE: Slowly setting up to build a Bridi Escape.
 

Brian,
A brief time under a map torch should soften the aluminum enought to tweek the header to the shape you need. I wouldn't butcher the canopy.

RE: Slowly setting up to build a Bridi Escape.
 

Could you maybe scoot the canopy a touch forward (or raise up) enough to clear the header?? I agree to not butcher the canopy... ;)

RE: Slowly setting up to build a Bridi Escape.
 

Brian,

On my Escape, I soaked some 1/4 sq. balsa strips in water and CA'ed them to the fuse top and set the canopy down on the rails. Raised the canopy by enough to clear the header. Because of my Webra LS and long pipe, I had to open up the back of the canopy to clear the pipe, hardly noticable unless you have a stock canopy to comapre.

Jim

RE: Slowly setting up to build a Bridi Escape.
 

What keeps the exhaust header from popping off the engine?  Is the header strapped to the plane to prevent this?

RE: Slowly setting up to build a Bridi Escape.
 

Brian,

looks peachy to me! Great news on the Rossi header. Could you post for comparison some pics of the engine overlaid on the plans with the ST header? Maybe you did this already in the other thread but it would be good to see the two headers in pics side by side.

Raising the canopy slightly like Jim suggests seems like an excellent idea. I know that Bob Hunt did this with his XLT build in a 1982 FM article. He made a canopy shaped " ring floor" to raise the canopy and provide some additional room for the pipe.

As far as the header goes, you will need an inlet in the canopy at the front of it, not only to allow the header into the canopy but also to allow air to pass through the canopy to cool things. If you raise the canopy enough you should only need a U-shaped inlet to pass the header and provide a little extra room around it. Likewise at the rear of the canopy you will want to turn it into an open exit which is often made in the shape of a slanted inverted U with the top of the canopy opening further forward than the base where you essentially only have two "fins" that attach to the fuse. Remember that, as with electrics, you need 3 times the exit area as the inlet area for good flow and cooling.

I suspect you will also end up cutting off an inch easily off the header in order to reach peak performance. The ST is a short stroke if I remember correctly and will clock higher than the more modern Japanese OS's and YS's - hence, shorter overall exhaust length. I'd plan for an 11x8 to a 12x8 on the ST, nothing more. I believe Hanno had an MK varioprop capable of doing 12x8" at max pitch on his Magic with this engine.

Build on!

David.

RE: Slowly setting up to build a Bridi Escape.
 

Usually only friction is needed for "soft mount" installations. An O-ring or a gasket of sorts keeps the head in position. The pipe is permanently fixed to the top of the fuse thereby preventing the header to disengage from the engine.

Brian was inquiring about RTV for this reason to produce a seal. Oh, in Italian engines there is also a spring retaining the header on to the engine via a metal ring that traps the header inlet opening. That ring and spring can be seen here in a Rossi installed in Chris' new EU-1A.

David.

RE: Slowly setting up to build a Bridi Escape.
 

Brian,
I forgot to mention that I cut some slots in the aft part of the canopy for additional cooling.

Will try to get and post some pics in a day or two.
Jim

RE: Slowly setting up to build a Bridi Escape.
 

We've tapped anywhere from the header to pipe entry stem to pipe large diameter. Any of these places works for standard venturi diameters. Some of the larger venturis employed by OS as I recall, were problematic and required a pump to run right. Definitely use Dean's techniques to set your pipe length. On your first couple flights, proof the pudding so to speak by unloading the model in a 15 degree dive at full revs. Start high please. If the pipe is set right, it should not cause much engine change. If pipe is too long, the engine will go fat and if too short (for the load you are running) it will pick up rpm as it went lean. This technique is tolerant of small load changes, like going from an 11x7 to an 11x8, for example. If you plan to use something like a 12x10 but are tuned for an 11x8, expect to retune.

McMaster Carr sells thin, around 1/32" thick silicone rubber tape. They also sell Teflon tape with silicone adhesive backing that you can use directly on the back end of the ally header to hold exhaust in. I use this stuff on my gassies at the teflon coupler interface and it works great. It works at the gas exhaust temp so it will have no issues handling alcohol exhaust

RE: Slowly setting up to build a Bridi Escape.
 

Absolutely! The 1st two pics are the actual ST header, the last are the Rossi header.

RE: Slowly setting up to build a Bridi Escape.
 

double post, sorry!

RE: Slowly setting up to build a Bridi Escape.
 

I posted a shot of the retaining spring, metal ring, and header to pipe silicone connection. The ring slips over the header and the spring attaches to 2 tiny holes drilled into the metal ring. This pulls the header tight against the exhaust.

The ST, as I understand, does not use the retaining spring. I went ahead and ordered it from Rossi anyhow. I thought it may be good to use it.

The pipe will be mounted to the fuse with a Hush Mount from Dave Brown products. If you wish, I can post a pic of this as well. Anyhow, the pipe and header are securely held in place with this as I understand.

This is a first for me, so I have more questions...

I do not have any instructions with my engine, and I refuse to ruin it.

What is the break in procedure? What fuel is best used with this engine?

I plan to set up a break-in stand, and post every adjustment I make with it. I want to make sure I treat this with the respect it deserves. [8D]

This means a LOT of pictures, a lot of novice questions, and patients from everyone reading.

There is no one I know in my area that understands how I want the engine tuned, so I will follow the Pappas article and hope you guys will tell me if I'm about to do some thing stupid. This could help others as well.

Deal?

Brian

RE: Slowly setting up to build a Bridi Escape.
 

ABC engine break in - simplified:

Light load prop - 11-5 or 11-6
More oil in the fuel ~25%
Start it and go immediately to full throttle. A rich two-stroke (500 to 1000 rpm down from peak)

Couple tanks like that and you're pretty much broken-in.

RE: Slowly setting up to build a Bridi Escape.
 

Sweet! Easy to do. Thanks


MTK-

There are so many options at McMaster Carr that I do not know for sure what I'm searching for. Can you post a link to the product?

Brian

RE: Slowly setting up to build a Bridi Escape.
 

Thanks Brian,

ok, it looks like life is going to be much easier with the Rossi header unless you play around with the ST portion aft of the bend. But I would keep the ST header as is - it would work perfectly on any inverted engine installation if you ever decide to build such a model. It will be easier to come by another engine than another header. Really what you need for the Escape is an S-shaped type header rather than a Z-shaped (Rossi) or flat Z-shaped (ST) which is what fuse top headers are.

What baffles me a bit is how on earth one gets the top screws of the engine mount bolted down - they will be way above the top of the FW. I think that would be the first thing I'd modify. Redesign the FW to look more like the one in this drawing. These are from a Sarpolus Hammer which I re-designed internally for a RE 25 setup - same concept as the Escape except the pipe hatch is built up and part of the model. I would also do away with the front top block and produce the cuts needed to pass the header in both the FW (as shown) and in a top sheet. The fuel tank installation will be much easier and carving a huge block to leave a 1/8" thick wall sounds tricky at best. You would then close the gap in the fuse for that area by laying up FG. It's going to have to be glassed anyway to withstand the heat of the header. Actually, I might even go with CF in that area. Make sure you use good epoxy!

David.

RE: Slowly setting up to build a Bridi Escape.
 

Heck,

it just occurred to me that one of the differences between the earlier ST X60 blue head RE and the later ST X61 TST silver head might be that the former is a ringed engine while the latter is ABC. I'll have to confirm that.

BTW Brian, Matt's suggestion to use Teflon tape which is silicone backed sounds like a great solution. If it is too thin, you can probably wrap it around itself much like one does with water plumbing joints (e.g., shower heads). Chances are that one circumference is all it takes.

David.

RE: Slowly setting up to build a Bridi Escape.
 

Just regular Teflon tape?

Mine is not ringed. Does this help?

Brian

RE: Slowly setting up to build a Bridi Escape.
 

http://shop.vendio.com/RossiEnginesU...762/index.html this is what you might need

RE: Slowly setting up to build a Bridi Escape.
 

On the Rossi exhaust, there is a rim that this ring sits in. The ST doesn't have one. The ring would be too thick and would roll in when installed.

I appreciate it.

Brian

RE: Slowly setting up to build a Bridi Escape.
 

Brian,
Here is a pic of the Escape canopy taped in place on the fuse. The additional "lift rails" don't show well here, actually they are only about 6 or 8" long and are at the front section of the canopy.

Also, a shot of the beginning of the coloe trim on the horizontal stab.

Cheers,
Jim

RE: Slowly setting up to build a Bridi Escape.
 

Jim,

nice Escape!

Did you raise the canopy due to the header or was it needed for the pipe?

David.

RE: Slowly setting up to build a Bridi Escape.
 

David,

I raised the front of the canopy to clear the header. The Webra Long Stroke I want to use needed the longest header in my stash and it was a bit too close to the canopy for my peace of mind.

Jim

RE: Slowly setting up to build a Bridi Escape.
 

Wow! I really like your Escape. I like how you handled the header issue. Gives me ideas...

Thank you.

Brian