New Composite ARF SU27
11-15-2017, 02:04 PM
#351
What valve are you using for the retracts. I was struggling with the same issue on the large jets using jet Tronic or other digital valves. I switched to BVM High Flow and have had no issues.
Behzad
Behzad
11-15-2017, 02:08 PM
#352
Jet Tronics digital in fact. May be worth fitting a mechanical valve to see if it can push a bit more air to the cylinders quicker. Would be easy enough to test by hand without having to permanently install and servo actuate as well. And I bet I can find a BVM high flow locally in a parts bin.
11-15-2017, 02:23 PM
#353
JT do a high flow electronic valve too ,but a trick I use is to use two valves, T’d on the air supply and Y lead the control lead
All the SU’s I’ve seen have JT valves and work fine even in flight.
All the SU’s I’ve seen have JT valves and work fine even in flight.
11-15-2017, 02:33 PM
#354
Hi Auburn
I just finished a Marchetti that I fitted Robart wheels / Break on which are pretty heavy. First installed the JT and it was struggling on the bench so I replaced it with BV valve, it is like you have no weight and the gear works with authority. I had not thought about this until I saw it on the forum for Extreme ARF F100. I think it would worth a try. Good Luck
Behzad
I just finished a Marchetti that I fitted Robart wheels / Break on which are pretty heavy. First installed the JT and it was struggling on the bench so I replaced it with BV valve, it is like you have no weight and the gear works with authority. I had not thought about this until I saw it on the forum for Extreme ARF F100. I think it would worth a try. Good Luck
Behzad
11-15-2017, 02:57 PM
#355
Hi Dave
I have one of those on a 2.5M Futura which I have added strut covers to. It struggles and would only lock the gear up when I turn the plane inverted (split S is always the first maneuver!) . I should try the 2 valves see what happens.
Behzad
I have one of those on a 2.5M Futura which I have added strut covers to. It struggles and would only lock the gear up when I turn the plane inverted (split S is always the first maneuver!) . I should try the 2 valves see what happens.
Behzad
11-15-2017, 03:44 PM
#356
I think I will try the two JT valves trick since I can just borrow the air brake valve to test tonight. I’ll post the result. Dave, do you drive different cylinders with each valve (ie nose off one and mains off another) or just tee both valves into the supply lines to all three cylinders?
11-15-2017, 08:48 PM
#358
Set this up with the valves I had on hand, and sure enough the gear goes up faster, sooner, and with more authority. I feel good about this setup. Just need to grab one more valve to replace the air brake valve I robbed.
11-15-2017, 10:10 PM
#359
I run the mains on one valve and nose on another. I just extend the tube to the nose cylinders to make the air flow much further since the nose will go much faster. Where possible I installl the valve driving the mains back nearer the units so shorter lines feeding air. On warbirds like the CARF P-47 I install one valve in each wing panel.
D
D
11-16-2017, 06:32 AM
#360
Makes sense. I have it working pretty well now with both valves feeding all three cylinders, but I did consider relocating a valve closer to the mains if this gives us any trouble. And dang how I wish these valves had festo fittings instead of barbs.
12-15-2017, 02:25 PM
#362
Interesting. That is not the same gear I had.
Couldn't find any pics on my phone so I took this one from the Intairco build on FB - it’s the same gear I had.
Couldn't find any pics on my phone so I took this one from the Intairco build on FB - it’s the same gear I had.
Last edited by Auburn02; 12-15-2017 at 02:28 PM.
12-15-2017, 06:41 PM
#363
Andreas Gietz at CARF just responded to my inquiry. The gear you guys have is the first series, it was manufactured by Matrix here in the US as far as I know. The more recent orders get shipped the Airtech gear. Andreas confirmed that the gear mount has to be cut slightly for the new gear to fit. The latest production models don't have this cross brace any longer and the Airtech retracts fit without modifications.
Thomas
Thomas
Last edited by bluelevel; 12-16-2017 at 05:51 AM.
12-18-2017, 07:09 AM
#366
Nice!
The one I built got maidened Saturday - flew awesome, but 2 things:
1. The Dubro tires do not hold up worth a damn, at least when the plane is sitting still on the gear. Flat spot after sitting for about 5 minutes so the airplane had a nasty bounce/wobble on taxi and takeoff, fortunately not bad enough to keep it grounded but they'll be replaced. Instinct told me not to trust them, but I know others used them successfully so we tried.
2. Lost a ventral in flight. Again instinct told me to secure them somehow better than just friction fit, but one worked its way out. Hopefully one of our local guys can fab up a replacement using the remaining one as a master.
The one I built got maidened Saturday - flew awesome, but 2 things:
1. The Dubro tires do not hold up worth a damn, at least when the plane is sitting still on the gear. Flat spot after sitting for about 5 minutes so the airplane had a nasty bounce/wobble on taxi and takeoff, fortunately not bad enough to keep it grounded but they'll be replaced. Instinct told me not to trust them, but I know others used them successfully so we tried.
2. Lost a ventral in flight. Again instinct told me to secure them somehow better than just friction fit, but one worked its way out. Hopefully one of our local guys can fab up a replacement using the remaining one as a master.
Last edited by Auburn02; 12-18-2017 at 07:21 AM.
01-11-2018, 10:18 AM
#368
I'm using 5'' dubros on mine, they fit more easily than the 5.5 ones, the only thing is that they don't hold up to much weight and a i got a flat spot on them as I leave the plane assembled all the time at my club, nothing terrible but you can notice a bounce while taxing....i want to try the robbart's slim 5" as they seem to be stronger but Robbart wont answer my email asking them abouth their weight....
Do you know if Matrix could upgrade existing LG to electric and how much that would be?? Now that I have the Joker with electric gear I want to forget about air pumps
Do you know if Matrix could upgrade existing LG to electric and how much that would be?? Now that I have the Joker with electric gear I want to forget about air pumps
01-11-2018, 10:40 AM
#369
Are your tires foam? I'm using the dubro metal hubs, thinking they use the real rubber tires.... Not plastic and foam ones... that was a huge negative for me with the carf gear.
Are your gear Johns? I would assume he could upgrade if he made them! I'll PM you his address.
Are your gear Johns? I would assume he could upgrade if he made them! I'll PM you his address.
01-11-2018, 10:45 AM
#370
Dubro makes 5" metal hub wheels? Never seen or heard of that product. Are there compatible brakes for them or would it use the same as the plastic hubs, where you glue on a rubber disc? Surprisingly the original brakes on the plastic hub Dubros work very well, but I'll echo skymaster68 in saying go with the 5" wheels, but not foam. I've handed the plane over to its owner but we're still evaluating wheel options. I think the Robarts are the way to go but we haven't made a change yet.
