[Hughes500E]

I ordered the BVM in tank clunk line, I have learned that the back of the tank is the best place to keep the clunk? Long brass line with a perfect bend towards the rear, then BVM Clunk line etc. Plumbing the tanks will be ok! Installing the UAT no problem (45deg), main tanks to UAT, OK (Tygon). UAT to pump.................

6mm to 3mm? 6mm to 4mm? I could possibly squeeze some 4mm on the UAT and I have a 4mm to 3mm Festo? What about the other side? 4mm straight to turbine? I have a 4mm Festo ball valve and a Hangar 9 Pro Filter!

It seems to me that the UAT should have smaller fittings to make the connection to the pump less arduous or the pump should have larger fittings. I'm sure 4mm line could starve an engine? When I redid the install in my Boomerang I was blessed with having the pieces already there to work with!

This new setup is hopefully going to invlove a new Jets-Munt VT-80!

Thanks for any help with this!

[Helijet]

Here is how I have done my installs from 12 lb thrust turbines - 38 lb.

I plumb my tanks using large Tygon tubing. Make sure that there is at least 1/2 inch gap between the pick up and the back of the tank. Large tanks may require a baffle. If using a baffle you must use a brass tube to connect pieces of tubing otherwise the baffle will cut the tubing in no time at all. Now.....I continue the use of tygon to a center line pick up tank which many refer to as a UAT or other such tank. Make sure to secure all line with wire. DO NOT USE Zip Ties as they do not tighten in a circular manner. They tighten in an elongated manner which could be a source of air leakeage. From the UAT it is important to use a large diameter tubing to prevent cavitation as well as ensure that the volume the pump needs to pull easily exceeds pump pressure output. These pumps can run at more than 60 psi. Use a polypropelene ( stiffer ) tubing supplied by the manufacturer of 6mm. To fit it over the nipple of the pump, place a small piece of 4 mm tubing over the inlet nipple and then push on the 6mm line. Secure with wire. The line from the pump to the engine should be a line consistant with the connection on the engine. In most cases 4 mm. It is a good idea to place a filter between the pump and the engine. I generally try to avoid too many festo connections between the UAT and the pump as festo work better with pressure as opposed to suction. 12 - 17 lb engines have pump voltages run between 2 - 3 volts larger engines up to 5 volts. The pumps can run much higher / we don't stress them but having a patent system is very important especially with smaller engines that are much more sensitive to micro bubbles.

Cheers
Dean W.
< the prof >

[flyboysnow]

or a p70 steve! working on finding a ride for the yak!

[kev-o]

You beat me to it Dean but hey I learned it from one of the best ,the professor is a great teacher.

[Hughes500E]

Thanks Dean, this is appreciated!

Steve

[Pauld]

Originally Posted by Helijet

Here is how I have done my installs from 12 lb thrust turbines - 38 lb.

I plumb my tanks using large Tygon tubing. Make sure that there is at least 1/2 inch gap between the pick up and the back of the tank. Large tanks may require a baffle. If using a baffle you must use a brass tube to connect pieces of tubing otherwise the baffle will cut the tubing in no time at all. Now.....I continue the use of tygon to a center line pick up tank which many refer to as a UAT or other such tank. Make sure to secure all line with wire. DO NOT USE Zip Ties as they do not tighten in a circular manner. They tighten in an elongated manner which could be a source of air leakeage. From the UAT it is important to use a large diameter tubing to prevent cavitation as well as ensure that the volume the pump needs to pull easily exceeds pump pressure output. These pumps can run at more than 60 psi. Use a polypropelene ( stiffer ) tubing supplied by the manufacturer of 6mm. To fit it over the nipple of the pump, place a small piece of 4 mm tubing over the inlet nipple and then push on the 6mm line. Secure with wire. The line from the pump to the engine should be a line consistant with the connection on the engine. In most cases 4 mm. It is a good idea to place a filter between the pump and the engine. I generally try to avoid too many festo connections between the UAT and the pump as festo work better with pressure as opposed to suction. 12 - 17 lb engines have pump voltages run between 2 - 3 volts larger engines up to 5 volts. The pumps can run much higher / we don't stress them but having a patent system is very important especially with smaller engines that are much more sensitive to micro bubbles.

Cheers
Dean W.
< the prof >

And I'm sure Stevo covered this with your last build but when using tie wire, use 2 wraps and make sure that the "tie" in the wire lines up with the point where it crosses the wrap wire. As with the zip ties, you want to ensure that the binding action doesnt pinch the tubing into a pear shape leaving a leak path.

In general, keep everything as large as possible in tubing size until you absolutely have to reduce it. That's why Dean said to put the 4mm tube to reduce from 6mm at the pump and not at the UAT. Also important is to use poly tubing and not Tygon anywhere on the suction side of the pump including between the UAT and the tank as this stuff can collapse under suction. With an 18lb turbine likely not a big deal but it can be on 120 size and up.

I'm looking forward to seeing your VT80. I have heard good things about it and heard a rumor from Peter A that the Merlin 140 is going at least partially in the same direction with the integrated valves, etc.

PaulD

[Hughes500E]

Thanks Paul, Stevo did go over tie wire with me and no blades near nipples too! All new stuff to me!

I just got all my bits from Todd at Dreamworks, very fast service! Very impressed! Still sanding the fuse but planning for the install as I go!

Steve

[Hughes500E]

Curious, why don't all jets with an internally mounted engine utilize a bypass assembly? Is it just offered by the higher quality manufacturers? Is there any reason why you wouldn't want to use one? I would guess that if the airframe (air intake) wasn't designed with a bypass in mind that putting one in could actually reduce power?

Thanks
Steve

[Pauld]

The general rule of thumb for bypass - as I understand it - bypass=more top speed and less static thrust, no bypass=somewhat the opposite. Bypass can also help with not pressurizing the fuse but you also have to be carefull with heat/installation issues.

PaulD

[Helijet]

Yuuuup....like he ^^ said !


d.w.