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JET LEGEND VIPER BUILD THREAD

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Old 11-08-2012, 12:34 PM
  #226
Jeremy_D
 
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Default RE: JET LEGEND VIPER BUILD THREAD

With my P80se - 9 mins, usually between 1/2 to 3/4 of one tank left. It is a slippery airframe, flies nicely around on half to 3/4 throttle. Goes vertical with ease at full throttle. My mate has a VT 80 in his, even better on the fuel, almost 1 tank is still full after 7-8 minutes.
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Old 11-10-2012, 11:28 PM
  #227
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Default RE: JET LEGEND VIPER BUILD THREAD

Hi Guys,

One of my struts sits slightly lower than the other, I have tried the air top up but to avail. I checked each strut's oil level and noticed the one sitting lower needs a top up. Can anyone offer any advice as to what weight of shock oil one would use? Is there a 'standard'

Thanks in advance

BTW just added another album of photos from last Sundays outing. I'm now up to 16 flights on the airframe and am loving every aspect of it. It really is a pleasure to fly.

[link=http://www.facebook.com/media/set/?set=a.304241703014133.61695.233530253418612&type=1]PHOTOS HERE[/link]

Jeremy
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Old 11-15-2012, 07:32 AM
  #228
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Default RE: JET LEGEND VIPER BUILD THREAD

I just put my deposit down for the Red and white HPAT scheme. These things are hard to get a hold of. I wanted the 2010 Hawk Scheme but not read until end of Jan at the earliest so I didnt want to chance it. I know how that goes!

ANyways hope to have it next month, JL says it has already shipped.
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Old 11-15-2012, 09:21 AM
  #229
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Default RE: JET LEGEND VIPER BUILD THREAD

Jeremy:

I had to top off one of the nose gear struts on Mike's airplane and I used standard hydrolic jack oil. It worked very well. I made up a small tool to inject the oil consisting of a syringe, tube and a standard air cylinder nipple. The nipple screws into the fitting on the gear strut and relieves the check valve, Then you can push the oil into the strut and remove the fitting to seal. Make sure the syringe and tube are connected to the fitting when opening the check valve or there will be oil everywhere.

Hope this helps.

Paul S, Global Jet Club Advisor
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Old 11-15-2012, 11:24 AM
  #230
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Default RE: JET LEGEND VIPER BUILD THREAD

Hi Paul,

Thanks for the info.

Jsut out of interest I emailed JL a few weeks bak to ask and this is what they had to say -

First, let out the air in the strut, the method is that push the air nipple by a small pin, and let out the air in the strut.

Remove the prevent twisting arm on the strut, seperate from the strut completely, then you can add the oil, and the standard is that filled up with the

steel strut. Then fit the arm on the strut again, add the air finally , it should be about 8kg.


I gave this a go and it worked great. I just need to get some softer oil for the strut now as it feels a bit stiffer than the other. I'll try and get some hydraulic oil and give it a go.

Thanks for the info

Cheers

Jeremy
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Old 11-15-2012, 11:57 AM
  #231
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Default RE: JET LEGEND VIPER BUILD THREAD

Actually just on the strut, while I had mine apart I had a good look at the way it all works and it is quite well thought out. The lower part (the steel part) contains the oil while the top half of the strut is all air driven. The top half looks like it consists of a rubber seal and a round disk that has a small pole going up through it into the top of the strut and a nut on the bottom. I also think there may be a small spring up in there. Once the strut is together and the air is pushed in it acts like a massive dampener when compressed. The top half helps stop the strut from compressing fully due to the air pressure which also pushes it back into place so the strut doesn't sit low. The oil takes the impact of the landing and allows the strut to compress and dampen the blow stopping any bounce like sometimes experienced with certain springs. I tried a 40wt oil and it is noticeably harder than the other strut. I have some 20wt and 25wt coming. JL only said they used the oil for a model car but couldn't elaborate on what rating.

The new oil arrives today so over the weekend i'll drain the other stuff and put up some photos of the internals that are visible.

My nose strut interestingly enough is a spring driven strut.

Cheers

Jeremy
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Old 11-15-2012, 12:22 PM
  #232
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Default RE: JET LEGEND VIPER BUILD THREAD

Jeremy:

Our first aiplane has the oil filled nose gear and springs on the mains. Later airplanes have spring on the nose and oil in the mains.

The original had the trailing link nose gear that collapsed when moving forward. That is why I added the oil. Now it acts very well and does not collapse on take off. I did not investigate the strut as you have. I just added the oil to the top of the strut to the max amount. This worked very well.

Paul S, Global Jet Club advisor
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Old 11-15-2012, 12:25 PM
  #233
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Default RE: JET LEGEND VIPER BUILD THREAD

Jeremy, those pics will be great to see. haven't had time to fly mine after the first four flights. remember I had problem with the nose strut of my JL Viper on the maiden.haven't had the chance to look at it since the 'make do' refill and am guessing will have to generally check all the gears before next flight.
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Old 11-15-2012, 12:28 PM
  #234
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Default RE: JET LEGEND VIPER BUILD THREAD

No worries I'll get some pics up. I remember your video where you had to fill it.

Please note though that the process I'm using for the mains is only for the mains as this is all I asked JL to clarify for me as my nose strut is sprung. The same process may not apply to the earlier models with oil filled nose struts and the method Paul and yourself used sounds like it worked for the oil filled nose struts.
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Old 11-16-2012, 04:18 AM
  #235
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Default RE: JET LEGEND VIPER BUILD THREAD

Very nice Jet !!!!

A rabbit 100 or jets munt vt 80 would be a good turbine for this jet ?

Best Regards
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Old 11-17-2012, 03:16 AM
  #236
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Default RE: JET LEGEND VIPER BUILD THREAD

VT 80 flies it fine off grass.

As promised here are the pics. They are a little grainy as they were off my iphone camera. I used 25wt and it seems to be a very close match to the stock oil. Maybe a 20 would also work but I'm happy with how it feels compared to the other strut and compression feel equal.

First pic show the inside of the upper strut. The plate is what the lower strut compresses against and the air acts as the spring. Other pics is of the lower strut empty and with the new oil.
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Old 11-21-2012, 09:50 AM
  #237
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Default RE: JET LEGEND VIPER BUILD THREAD



HI dos any body no if JL VIPER has wash out in the wings and if there isany dihedral on the wing.
is the wing,  turbine and tail plane all set at 0  incidence to the datium line
Thanks Jim.

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Old 11-21-2012, 10:45 AM
  #238
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Default RE: JET LEGEND VIPER BUILD THREAD

1.5 degree washout on both wings.

Mike
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Old 11-22-2012, 01:13 AM
  #239
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Default RE: JET LEGEND VIPER BUILD THREAD

Thanks Mike thats one part of the puzzle found, any body now ware the aouther parts are Reincidence / dihedral
Jim
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Old 11-22-2012, 03:59 AM
  #240
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Default RE: JET LEGEND VIPER BUILD THREAD

Hi jim,

I'm not sure about the incidence but I can help with the dihedral. It definitely has it. Some pics to show the amount
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Old 11-22-2012, 06:31 AM
  #241
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Default RE: JET LEGEND VIPER BUILD THREAD

Thanks Jeremy, That will be two parts of the puzzle found, just nead wing / tail plane / turbine incidence.
Jim.
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Old 12-10-2012, 08:06 AM
  #242
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Default RE: JET LEGEND VIPER BUILD THREAD

Got mine in hand. I am going to go with the hitec HS-7954SH servo fo the elevator and the futba S3051HV for the rest of the jet. Unfortunately it will be run on 6V not 7.2 because my retract and brake servos are not rated for 7.2V.

Can someone walk me through the landing sequence? I had an MB f-86D, basically I would drop the flaps and keep some power on, then before my finaly turn I would cut power, doint the final 180 turn to land completely un powered. I found it to land just fine this way with an occasional bump with power in case I started getting slow.

My f-16 on the other hand, no flaps but when I drop the gear I am at 50% power all the way down, only dropping power a few feet before touch down.

So is this a power on jet, a power off jet, or somewhere in between?

ALso anyone see any harm in not using take off flaps?
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Old 12-10-2012, 02:18 PM
  #243
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Default RE: JET LEGEND VIPER BUILD THREAD

Hopefully I can help answer your quests based on mine flying with a P80se

Take off flaps - not needed but hand. I have had about 10 flights without and 10 flights using them. I prefer them, just gets it airborne a little bit smoother and quicker.

Landing - my sequence is this. Gear circuit is at first stage flap and lg down and throttle between 1/4 and 1/2. Down wind leg go to full flaps, start to bring back power to around 1/4 or close by so it keeps flying but it is draggy now. Before final turn pull back power to under 1/4 and slowly come off it pulling back to idle once level over the threshold. I've linked to my video below. Takeoff is without flap, downwind leg was full flap and the landing which was my second ever on this plane was a little quicke as I came off the power a bit later than I do now.

http://youtu.be/fYxts6fzSAk

Hope this helps

Cheers

Jeremy
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Old 12-10-2012, 02:45 PM
  #244
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Default RE: JET LEGEND VIPER BUILD THREAD

Thanks for the info, it sounds like the same as my f-86D except I dont use any flaps for gear pass, only go to full flaps on leg before final. Other difference is I tended to do my final turn with idle power unless there was decent wind I would keep power on through this turn.

First couple landings I will keep a little under 1/4 power in final turn, only going to idle on final leg.

Are you using any crow at all?
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Old 12-10-2012, 03:03 PM
  #245
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Default RE: JET LEGEND VIPER BUILD THREAD

No crow, you could go to idle but you would need to be descending with some height to keep the speed up
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Old 12-10-2012, 03:08 PM
  #246
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Default RE: JET LEGEND VIPER BUILD THREAD

Sounds like it is exactly like my old f-86D, except it wont have all that nasty dutch roll!

I'll be opening mine xmas morning and then commence building. I am certain I will have questions and hope that my gear doesnt need any modifications.
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Old 12-11-2012, 12:47 AM
  #247
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Default RE: JET LEGEND VIPER BUILD THREAD

Use crow, it transfoms this model into an absolute dream on landing.
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Old 12-11-2012, 12:51 AM
  #248
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Default RE: JET LEGEND VIPER BUILD THREAD

How much up aileron deflection are you using? I wouldn't mind giving it a go. Also I'm guessing you are only using it on full flap?
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Old 12-11-2012, 01:04 AM
  #249
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Default RE: JET LEGEND VIPER BUILD THREAD

Correct Jeremy, full flap only.
I'll measure it next time out, from memory I used a fair bit, it'll land at walking pace and the crow sets a nice aoa, it virtually lands itself.
I used to have an Elan which I thought was the best model of any type that Ihave flown but this Viper is better.
If I had my time over this is the way I would go to learn how to fly jets, it has a massively wide flight envelope from trainer to out and out rocket simply depending on the amount of throttle you give it!
Gary.
Cannot upload pics, what's wrong with this site!
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Old 12-11-2012, 01:59 AM
  #250
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Default RE: JET LEGEND VIPER BUILD THREAD

If you could measure and let me know that would be great. I would be keen to give it a go. You are right that it is a great jet in it's flight envelope. Are you needing much power with Crow on? Also where did you settle with your CG? The pic below shows where mine is, just slightly nose heavy in this location with gear up and uat full. Seems to be okay after 16 flights. I'm still experimenting with how slow it can go, I think Crow should be fun!
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