LA jetguy

Barry is using individual vent line for each of the side main tanks.... I'm planning on T'ing the vents using 8mm into one vent .... I'm using all large gauge (8mm) tank fittings including cluck from JMP.....Any pros or cons on T'ing the vent line??

Thanks

David

BBDRIVER

My Feedback: (15)

Hi David

I too have a separate vent on each side main tank. I used extra large tubing through out the entire fuel system, and used the medium CAT airtraps. I believe if you "T" the vent line you'll probably build a lot of pressure in the system as you have to "MOVE A LOT OF FUEL" when you fuel/defuel. I had this happen in my twin Yellow F-18. You could virtually see the tanks expand and contract.

Hope this answers your question
Cheers

FenderBean

i always use separate vents, since it helps lower the pump voltages as well. Anything I can do to make the load on the pump less is worth it for me.

mr_matt

My Feedback: (10)

David if you separate the vent lines you of course need 2 taxi tanks (if you need taxi tanks that is).

With 8mm line I would think you could get away with one but you are running big motors?

EDIT: Are you guys flying this week?

Craig B.

Hi Matt,

JMP make a taxi tank for twins. I would suggest 2 vents.....one partial blockage in a single vent and it would be lights out for both engines.


http://www.dreamworksrc.com/catalog/...-Overflow-Tank

LA jetguy

Thank you Guys for your inputs... much appreciated... I have seen Barry using a BVM taxi tank T'ing the vents from the outside into one taxi tank... That is exactly how I will do it.. the T would be outside and connected to the tubing to the taxi tank...

Matt.. yes as usual we will fly this Thursday (10/2)... I will not be able to be at field this Saturday but try to make it on Sunday... Hope to see you..

David

mr_matt

My Feedback: (10)

Hmmmm T outside of the plane. That is a better idea. We had a plane with 2 widely spaced vents and 2 taxi tanks and it was a pain.

David I will try to make it Thursday.

LA jetguy

Yes... Im using the two overflow vents from Todd:




Look forward to see you Thursday...

FenderBean

my f-16 had dual vents as well and I used/use a single tank with a T fitting branched into two lines that connect to the vents. Works great, plus it less stuff to carry around/keep up with.

WimB

My Feedback: (1)

I will go with a single vent........ very short lines anyway, and take this into consideration: the Tomcat has about 8l of fuel on board, and on average this would be emptied in 8 minutes. that is 1l of air/min that has to go into the tanks.... this is peanuts through a 6mm festo line..... i have a similar setup in my SM F-15: the two main tanks vent via a T into a single line, and this is done with tygon line.........never had a single issue up to yet..........

Wim

FenderBean

What EV5 valve is everyone using I dont see any listed at dreamworksrc anymore. I thought about getting one from SM but not sure, Im trying to get the lightest setup possible. I have some robart 2 way valves like I used on my F-15 so I may just do servo actuated valves.

WimB

My Feedback: (1)

Fender,
M
The EVU 5in1 is indeed not a good option for the Tomcat, (Mick was right all along) as it has no provision to sequence the main gear doors. I have one, and I must admit that I'm not sure on how I'm going to solve it.

to me there are three options:

one is to use the Powerbox Sequencer with three EVU-2 valves and dump the 5-in-1. in my case, this will mean rearranging some outlets ont the powerbox, since all are already in use (all 24....). I will have to add a separate EVU1 for the brakes then as well. this will also entail a redesign of my removable module.......

I could also try to figure out a setup with button valves on the doors, to sequence them. this however adds to the complexity of the air setup and possibility of leaks....

third is a mix of the 5-in-1 with the sequencer on the powerbox.... means no extra hardware, but makes for a complex setup of the combo 5-in-1 and the powerbox, to get the two sequencers to work together.......

pfffffffffff..............

mick15

Why not use SM's simple little cockpit valve with a servo slow, works for me.

m

WimB

My Feedback: (1)

Mick,

'cause I don't have a second valve like that........

Wim

mick15

Buy one

WimB

My Feedback: (1)

haha, that is to the point indeed....

oh I just don't know yet how I'm going to tackle it, lots more to do in the meantime.....

Wim

FenderBean

Win that's what I was going to do, or you can use a simple button valve for the second gear door. I like using button valves for canopy locks as well. Saves you and extra valve and in this case it van save two.

mick15

I don't think a button valve will work, the main doors cannot open together.

m

WimB

My Feedback: (1)

Question:

where did you guys exit the cables coming from the wing servo's? I was planning on routing them to the front of the wing, forward from the main spar, but there's no way to get to the root of the wing that way.... only route I see is exiting between the two carbon "dowels"... I wanted to avoid this, because of the possibility of the cables getting hung up when sweeping the wings.......

Wim

mick15

Haha I was waiting for this question...........I bored a hole from the rear of the swing radius through the main spar into the cavity where the flap servo goes.If you go onto Skymaster F14 page there is a pic of the wing being moulded.m

WimB

My Feedback: (1)

Mick,

could you clarify "rear of swing radius"?? pic perhaps?

Wim

mick15

The hole in front of the main rod goes into the flap servo aperture, it's then easy to join it from the rear of the swing radius. I did ask John the facilitate this but had no response.m

WimB

My Feedback: (1)

So, if I read correctly: you drilled the hole in the picture, just in front of the dowel, all the way to the flap servo cavity?

Wim

mick15

Correct, then drilled from the flat part of the radius through the carbon spar into the space where the first hole is. If you are using PWM servos the hole only has to be 5mm.m

WimB

My Feedback: (1)

okay, I'll have a good look at the pic of the open wing then...
Is this the route you followed?