McLaren Mercedes ViperJet MAIDEN
03-31-2009, 09:44 AM
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RE: McLaren Mercedes ViperJet MAIDEN
Sandor,
Good point I forgot to add, that we also added another large air tank for the gear and it was helpful but I still needed a lot of presure to get the gear up. Over 50 flights now with no problems.
Ron
Good point I forgot to add, that we also added another large air tank for the gear and it was helpful but I still needed a lot of presure to get the gear up. Over 50 flights now with no problems.
Ron
03-31-2009, 09:51 AM
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RE: McLaren Mercededs ViperJet MAIDEN
ORIGINAL: arizonasun25
Mark,
I was flying one of the first SM Viper jets here in the states. What we found with the gear is you need between 100 to 125 lbs of presure to get the main gear up. What happens is the strut gear doors catch a lot of resistance at take off and usually hold one gear or the other. So I have found 2 different fixes for this problem 1 more air presure and the second take off with take off flaps and flip the gear switch the second you lift off. If you notice my video the gears is up the second I leave the ground. If you build up to much speed one gear will hang and then you will have to fly inverted for a few seconds to get the gear down, that would be your 3rd option.
Hope this helps.
Ronald R Long
ORIGINAL: schroedm
Scott, I don't think there are any issues with the gear. I'm a bit confused as to why I had problems. I have cycled the gear a few dozen times in the workshop and 2 or 3 times on the ground before the maiden with no issues at all.
I am using the new AirPower all in one PRO valve and it seems to work fine. I can only assume that pumping to 80PSI, whilst fine on the ground is insufficient in the air. The valve is rated to 100PSI so I hope the extra 20 PSI does the trick next time. I will also check the gear over this weekend. Haven't pulled it out of the van yet.
Scott, I don't think there are any issues with the gear. I'm a bit confused as to why I had problems. I have cycled the gear a few dozen times in the workshop and 2 or 3 times on the ground before the maiden with no issues at all.
I am using the new AirPower all in one PRO valve and it seems to work fine. I can only assume that pumping to 80PSI, whilst fine on the ground is insufficient in the air. The valve is rated to 100PSI so I hope the extra 20 PSI does the trick next time. I will also check the gear over this weekend. Haven't pulled it out of the van yet.
I was flying one of the first SM Viper jets here in the states. What we found with the gear is you need between 100 to 125 lbs of presure to get the main gear up. What happens is the strut gear doors catch a lot of resistance at take off and usually hold one gear or the other. So I have found 2 different fixes for this problem 1 more air presure and the second take off with take off flaps and flip the gear switch the second you lift off. If you notice my video the gears is up the second I leave the ground. If you build up to much speed one gear will hang and then you will have to fly inverted for a few seconds to get the gear down, that would be your 3rd option.
Hope this helps.Ronald R Long
Gordon
03-31-2009, 10:11 AM
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RE: McLaren Mercededs ViperJet MAIDEN
Cheers Ron,
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
03-31-2009, 10:19 AM
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RE: McLaren Mercededs ViperJet MAIDEN
I like your idea Gordon.
There has to be a better solution than 125psi. Im suprised an additional tank didnt help much either.
I always want to be able to cycle the gear at a minimum of twice during a flight and it sounds like your lucky if you get one. I dont want to fly inverted to get them to close. I wonder if a BVM high flow valve would work any better?
Do the gear need better cylinders or larger nipples?
Scott
There has to be a better solution than 125psi. Im suprised an additional tank didnt help much either.
I always want to be able to cycle the gear at a minimum of twice during a flight and it sounds like your lucky if you get one. I dont want to fly inverted to get them to close. I wonder if a BVM high flow valve would work any better?
Do the gear need better cylinders or larger nipples?
Scott
03-31-2009, 10:21 AM
#30
RE: McLaren Mercededs ViperJet MAIDEN
ORIGINAL: schroedm
Cheers Ron,
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
Cheers Ron,
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
it will just bleed air thru the outlet Mark if the pressure is to high..
i do know these oleo,s are pretty darn long , did you use 3 or 4 mm tubing towards the gear?
using restrictors? , the gear needs some speed going up .
if i am not mistaking the retracts are the same as the "old"mb339.
if you use long tubing and thin its like trying breathing thru a straw that is 10 feet long..
03-31-2009, 10:27 AM
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RE: McLaren Mercededs ViperJet MAIDEN
Lets say one were to fly at a scale event and it was necessary to display retracts, retract then extend, then take off and retract gear and fly specified manuevers, then fly slow fly by with gear extended, then retract them, complete specified manuevers, then extend gear and land. This is what the gear need to be able to do at a minimum for me.
Scott
Scott
03-31-2009, 10:29 AM
#32
RE: McLaren Mercededs ViperJet MAIDEN
Mark wrote: <<<OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!>>>
Ron did not say that. He said you need to get off the ground quickly using flaps and click the retracs right away. If that does not work then put them down, roll inverted and retrac again, they will go in while the jet is inverted. I am surprised to read that the EV valve is rated 100psi max?? I have always used 120lbs in my air systems.
V..
Ron did not say that. He said you need to get off the ground quickly using flaps and click the retracs right away. If that does not work then put them down, roll inverted and retrac again, they will go in while the jet is inverted. I am surprised to read that the EV valve is rated 100psi max?? I have always used 120lbs in my air systems.
V..
03-31-2009, 10:32 AM
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RE: McLaren Mercededs ViperJet MAIDEN
ORIGINAL: digitech
it will just bleed air thru the outlet Mark if the pressure is to high..
i do know these oleo,s are pretty darn long , did you use 3 or 4 mm tubing towards the gear?
using restrictors? , the gear needs some speed going up .
if i am not mistaking the retracts are the same as the "old"mb339.
if you use long tubing and thin its like trying breathing thru a straw that is 10 feet long..
ORIGINAL: schroedm
Cheers Ron,
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
Cheers Ron,
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
it will just bleed air thru the outlet Mark if the pressure is to high..
i do know these oleo,s are pretty darn long , did you use 3 or 4 mm tubing towards the gear?
using restrictors? , the gear needs some speed going up .
if i am not mistaking the retracts are the same as the "old"mb339.
if you use long tubing and thin its like trying breathing thru a straw that is 10 feet long..
Sandor,
All tubing and fittings are 3mm. The gear didn't strike me as being that unusually long/large or heavy. I do have restrictors on the lines though about 1" from the valve. I guess I could start by removing the restrictor on the 'up' line? They were added in an attempt to stop the gear ripping itself out and shaking the paint off!!
What are the downsides to 4mm tubing all the way to the cylinders and then dropping from 4mm to 3mm just before the cylinder?
Cheers,
mark
03-31-2009, 10:33 AM
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RE: McLaren Mercededs ViperJet MAIDEN
ORIGINAL: Vincent
Mark wrote: <<<OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!>>>
Ron did not say that. He said you need to get off the ground quickly using flaps and click the retracs right away. If that does not work then put them down, roll inverted and retrac again, they will go in while the jet is inverted. I am surprised to read that the EV valve is rated 100psi max?? I have always used 120lbs in my air systems.
V..
Mark wrote: <<<OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!>>>
Ron did not say that. He said you need to get off the ground quickly using flaps and click the retracs right away. If that does not work then put them down, roll inverted and retrac again, they will go in while the jet is inverted. I am surprised to read that the EV valve is rated 100psi max?? I have always used 120lbs in my air systems.
V..
I was joking - I thought that would be quite a cool manoeuvre [X(]
Mark
03-31-2009, 10:34 AM
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RE: McLaren Mercededs ViperJet MAIDEN
ORIGINAL: schroedm
Cheers Ron,
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
Cheers Ron,
OK, so the definitive answer is 125PSI, roll inverted and hit the switch the minute the wheels leave the ground. Cool!
Out of interest, are you using the Evo Pro valve? Says on there limited to 100PSI but if you're using yours at 125 without problems, so will I.
Rgds,
Mark
. We had a bit of a learning curb with these gear. Yes we are using the new pro valve. It will handle a 125 lbs no more though! there is no restrictors on the lines we are using Dream works heavy duty air line. what I think it is is the strut doors are acting like large flaps. they catch the air at a certain angle. You can see the gear closes about 3/4 the way on one side and then hangs. It does not happen all the time. The key is fliping the switch at the slowest take off as possible that is why I would sudgest using take off flaps. A nice slow take off hit the switch and they go right up smooth as silk. Hope this helps. It really is not that bad.Ron
03-31-2009, 10:44 AM
#36
RE: McLaren Mercededs ViperJet MAIDEN
That reminds me of when I was in high school and my car needed some work and when I came to a stop sign I had to brake with my left foot and keep giving it gas with my right foot or else it the engine would die.
Wouldnt it be better just to fix the problem?
I would want them to work at least three times and go up nice and slow. LIke the Airworld Hawk gear.
Scott
Wouldnt it be better just to fix the problem?
I would want them to work at least three times and go up nice and slow. LIke the Airworld Hawk gear.
Scott
03-31-2009, 10:46 AM
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RE: McLaren Mercedes ViperJet MAIDEN
Scott,
look at this video and tell me if you don't think the problem is fixed. Just flip the switch asap upon take off. No problem. the gear are tall and it takes a bit of leverage to get them up.
http://www.youtube.com/watch?v=x7VwEeB2Spk
Ron
look at this video and tell me if you don't think the problem is fixed. Just flip the switch asap upon take off. No problem. the gear are tall and it takes a bit of leverage to get them up.
http://www.youtube.com/watch?v=x7VwEeB2Spk
Ron
03-31-2009, 10:47 AM
#38
RE: McLaren Mercedes ViperJet MAIDEN
The 5U-Pro valve is rated to 170 psi according to the manual http://www.dreamworksrc.com/Tips_Mods/ev5upro.pdf I think that air lines would be the restriction in this case if you would like to increase the pressure of your system.
I have two (2) of these valves (Skymaster MB-339 and Composite Arf Tucano) and I haven't had any problems with the retracts (and both planes have big retracts...). I always use 105 psi and I have two (2) Robart XL air tanks for the retracts and one air tank for the brakes. I0m using restrictors in the lines in order to slow down a little bit the retract speed.
I'm interested on this problem since I'm thinking on buying a Viper in the near future....
I have two (2) of these valves (Skymaster MB-339 and Composite Arf Tucano) and I haven't had any problems with the retracts (and both planes have big retracts...). I always use 105 psi and I have two (2) Robart XL air tanks for the retracts and one air tank for the brakes. I0m using restrictors in the lines in order to slow down a little bit the retract speed.
I'm interested on this problem since I'm thinking on buying a Viper in the near future....
03-31-2009, 10:47 AM
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RE: McLaren Mercededs ViperJet MAIDEN
Hi Ron,Mark
Yes the doors fitted to oleos and high airspeed when retracting is the reason for all your problems. On the ground no problems. But in the air different story. I have taken off the small doors and it work 5 times on 100psi no problem in air. As soon as the small doors are fitted, the 2 sec delay (i think this is max) is not enough on the electronic valve and the wheels close on top of fuselage doors or 1 gear hang out.
So use high flow valves or thicker tubing with more air reservoir. Not had the change to do conversion but i think this might work.
Regards
Morne
Yes the doors fitted to oleos and high airspeed when retracting is the reason for all your problems. On the ground no problems. But in the air different story. I have taken off the small doors and it work 5 times on 100psi no problem in air. As soon as the small doors are fitted, the 2 sec delay (i think this is max) is not enough on the electronic valve and the wheels close on top of fuselage doors or 1 gear hang out.
So use high flow valves or thicker tubing with more air reservoir. Not had the change to do conversion but i think this might work.
Regards
Morne
03-31-2009, 10:55 AM
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RE: McLaren Mercedes ViperJet MAIDEN
Morne,
Thanks for the tip. part of the problems that I had were my own fault I had only put one hinge in the middle of the gear door and it was tweaking in the air when trying to retract. So I took the doors off and there was no problem. Then I fitted them on with 2 hinges per door. like the pro version comes from Sky Master. It was definatly better but still from time to time you might have a gear hang. Not really a problem any more.
Ron
Thanks for the tip. part of the problems that I had were my own fault I had only put one hinge in the middle of the gear door and it was tweaking in the air when trying to retract. So I took the doors off and there was no problem. Then I fitted them on with 2 hinges per door. like the pro version comes from Sky Master. It was definatly better but still from time to time you might have a gear hang. Not really a problem any more.
Ron
03-31-2009, 10:55 AM
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RE: McLaren Mercededs ViperJet MAIDEN
Tut. [>:]
Oh well, makes for a more impressive flight if I take off and roll into an inverted circuit [8D]
I did hit the switch fairly soon after the take off. If you watch the video though you'll notice the right had gear is trying to retract as I am banking left so is up against the air flow even more.
I did notice on the Florida Jets coverage that Ali rolls his during the gear cycle - crafty little bugger
M
Oh well, makes for a more impressive flight if I take off and roll into an inverted circuit [8D]
I did hit the switch fairly soon after the take off. If you watch the video though you'll notice the right had gear is trying to retract as I am banking left so is up against the air flow even more.
I did notice on the Florida Jets coverage that Ali rolls his during the gear cycle - crafty little bugger
M
03-31-2009, 11:00 AM
#43
RE: McLaren Mercedes ViperJet MAIDEN
Ron,
You probably have more time on this bird than anyone and while you have found a fix, its not the solution. That fix only being to fly around with gear up, not actually working correctly.
It would not be possible for you to extend the gear in flight and retract them with your current setup.
We need to get hold of Anton to correct the gear.
Scott
You probably have more time on this bird than anyone and while you have found a fix, its not the solution. That fix only being to fly around with gear up, not actually working correctly.
It would not be possible for you to extend the gear in flight and retract them with your current setup.
We need to get hold of Anton to correct the gear.
Scott
03-31-2009, 11:01 AM
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RE: McLaren Mercedes ViperJet MAIDEN
Mark look at my video and you will see the gear does go right up. However if you do not use take off flaps the same hanging gear problem will occure.
http://www.youtube.com/watch?v=x7VwEeB2Spk
Ron
http://www.youtube.com/watch?v=x7VwEeB2Spk
Ron
03-31-2009, 11:03 AM
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RE: McLaren Mercedes ViperJet MAIDEN
Scott,
You are correct. There is no way that I can put the gear down in flight and then put them back up if I wanted to, without rolling inverted. Just is not going to happen.
Ron
You are correct. There is no way that I can put the gear down in flight and then put them back up if I wanted to, without rolling inverted. Just is not going to happen.
Ron
03-31-2009, 11:05 AM
#46
RE: McLaren Mercedes ViperJet MAIDEN
It look like this one is hanging also. Speed up to 1:08
http://www.youtube.com/watch?v=SCiuL...eature=related
Wouldnt it be cool if they worked that well?
http://www.youtube.com/watch?v=SCiuL...eature=related
Wouldnt it be cool if they worked that well?
03-31-2009, 11:06 AM
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RE: McLaren Mercedes ViperJet MAIDEN
Yep! Looking good Ron - they REALLY ping up compared to my video!
OK, steps as follows I think...
1. Remove restrictor in up line (air resistance will slow them up anyway)
2. Move up from 80PSI to 120PSI
Test Fly
3. Add additional tank
Test Fly
4. Switch to 4mm line
OK, steps as follows I think...
1. Remove restrictor in up line (air resistance will slow them up anyway)
2. Move up from 80PSI to 120PSI
Test Fly
3. Add additional tank
Test Fly
4. Switch to 4mm line
03-31-2009, 11:08 AM
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RE: McLaren Mercedes ViperJet MAIDEN
ORIGINAL: schroedm
Yep! Looking good Ron.
OK, steps as follows I think...
1. Remove restrictor in up line (air resistance will slow them up anyway)
2. Move up from 80PSI to 120PSI
Test Fly
3. Add additional tank
Test Fly
4. Switch to 4mm line
Yep! Looking good Ron.
OK, steps as follows I think...
1. Remove restrictor in up line (air resistance will slow them up anyway)
2. Move up from 80PSI to 120PSI
Test Fly
3. Add additional tank
Test Fly
4. Switch to 4mm line
Ron
03-31-2009, 11:10 AM
#49
RE: McLaren Mercedes ViperJet MAIDEN
Don`t forget the mains (tires) are huge too. I bet a smaller, lighter set of wheels and brakes would be a cure even with the strut doors connected.
Scott, the reason why Anton didn`t catch this problem is all of his test flight vids are with fixed gear...
V..
Scott, the reason why Anton didn`t catch this problem is all of his test flight vids are with fixed gear...
V..
03-31-2009, 11:13 AM
#50
RE: McLaren Mercedes ViperJet MAIDEN
The Jet Legend T-45 has the same problem with the airflow hitting the main gear doors and causing the gear to hang. I used an elastic cord "assister" to get mine up, but Mike Lin made a much more elegant solution that might work here. See the pictures below of what Mike did...
Bob
Bob