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Another Skymaster Viper

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Old 05-16-2010, 08:49 PM
  #1301
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Default RE: Another Skymaster Viper

Stig,

Any chance you could share your setup with me yet?

Cheers

Jan

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Old 05-16-2010, 09:07 PM
  #1302
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Default RE: Another Skymaster Viper

Only one for me today but mine was special as it was the maiden flight.







And the inside view.

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Old 05-16-2010, 10:03 PM
  #1303
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Quote:
ORIGINAL: Springbok Flyer

Gonzalo,

A work-of-art mate! Well done!

What is the total weight of your Viper?

Cheers

Jan
Hi Jan, thank you for the compliments! as soon as i do the CG I will let you know the final weight..... so far it feels quite light...

Regards,

Gonzalo
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Old 05-17-2010, 12:21 AM
  #1304
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Quote:
ORIGINAL: Springbok Flyer
Stig,
Any chance you could share your setup with me yet?
Cheers
Jan
Hey Jan.
Of course.
The throws are still the same as per manual except for the rudder, which now has 40 mm.
I found that 40 % Expo was perfect for elevator, allthough I nomally don't go further than 25%.
I moved the CG a bit forward. I think I'm at 225 mm now.
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Old 05-17-2010, 04:25 AM
  #1305
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Default RE: Another Skymaster Viper

Nice one Sverrir !!!! i take it, that everything worked as it should of done? what did you think of it?

Any issues with the gears doors trying to open in flight? After opening the right main door another 3mm, mine worked flawlessly yesterday, with none of the doors or gear trying to come down, in any of the manouvers we tried


Jan for what it's worth my set up, as done by Ali is

Elevator as per book
Rudder 65mm
ailerons as much as possible (5mm more than book, if i remember correctly, measured from the outer part of the aileron)
flaps as per book
10% expo max on all surfaces

Duncan
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Old 05-17-2010, 08:49 AM
  #1306
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Default RE: Another Skymaster Viper

Yes, to say it was good would be an understatement, it was fantastic! Smooth and hardly needed any correction, two clicks on the trim and even though it was blowing about 14 knots and gusting 18-20 she didn't notice that up in the air.

I'm seeing the gear doors opening like so many others, I'll probably need to do the "Duncan mod" to get them to behave properly.
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Old 05-17-2010, 09:55 AM
  #1307
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Default RE: Another Skymaster Viper

I'll take some pictures tonight of the new pick up point for the rams and if possible the new position where they mount off the former. It's made a hell of a difference to mine. The doors are solid as is the gear.

I haven't used 4mm tubing, but swapped out the chinese air line for BVM stuff and running 120psi through the airpower unit. Cycling the gear uses 10psi out of the 3 large air tanks. I have 2 air tanks for the brakes, which work really well, they held the model on the tarmac at almost full throttle yesterday, when Ali did a launch control styley take off

Duncan
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Old 05-17-2010, 10:03 AM
  #1308
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Default RE: Another Skymaster Viper

That was full 160 sx power it was holding ( For at least 5 seconds before I released ) The VJ has some of the best brakes of any jet. They hold the plane back against all that power and bring it to a stop even after a hot landing without flat spotting the tyres.
We should all follow Duncan's retract/ door set up as its the best I have seen to date. It cleans up perfectly on take off ( no slowing down required ) cleans up perfectly in flight even under load and speed!
Yeti... You need to be making use of those flaps. Both take off and landings with the VJ are so much nicer with flap!
Regards Al


Just to let you guys know.. We now have the full Viper jet vinyl sets in stock.
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Old 05-17-2010, 10:37 AM
  #1309
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Default RE: Another Skymaster Viper

Duncan,

please pictures please pictures!!! I want thoese doors to be close on take off!

Thank you,

Gonzalo
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Old 05-17-2010, 10:56 AM
  #1310
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Default RE: Another Skymaster Viper

Noted, I'm also booking you for some VJ flying early in July.
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Old 05-17-2010, 10:56 AM
  #1311
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Default RE: Another Skymaster Viper

See page 22, post 533 for gear door mod I made up. The doors never open in flight.
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Old 05-18-2010, 01:18 PM
  #1312
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Default RE: Another Skymaster Viper

Today I made first three flights with my VJ with slotted flaps und crow setting.
Slotted flaps 60° down (for landing), Aileron 10 mm up at the end, Elevator neutral. At my first flight I have Aileron 3 mm down during crow. Thats not good, nose goes tu much down, so I correct the elevator to neutral.
I'm absolute happy with this configuration. At the 3. flight I made a steep final approach of about 30°, without speed increase.
Conclusion; this modifications are worth to do - first impression was I fly another jet, not compare as before.
I recommend this upgrade.
Brg
Fritz
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Old 05-18-2010, 02:41 PM
  #1313
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Default RE: Another Skymaster Viper

Can I order online the 2M Viper decal set? Do you have a link you can post?
Thanks,
Bob
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Old 05-18-2010, 03:04 PM
  #1314
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Default RE: Another Skymaster Viper


Quote:
ORIGINAL: R_Belluomini

Can I order online the 2M Viper decal set? Do you have a link you can post?
Thanks,
Bob
Hi Bob

Ali has then in stock, just email him at jets@alshobbies.com and he'll sort you out

cheers

Duncan
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Old 05-18-2010, 03:27 PM
  #1315
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Default RE: Another Skymaster Viper

Hi All, I am in the process of building the Large Viper. Below is a photo of the control horns that came with the kit. All the instructions show the large horns for the control surfaces. Did I get the wrong ones or has there been a change in the instructions.
thanks
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Old 05-18-2010, 08:57 PM
  #1316
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Default RE: Another Skymaster Viper

Thinking of putting together a Viper. Noticed a lot of talk on the gear door cylinders and would like to know what the ideal way to go would be. I,m thinking of getting a bare kit and doing my own gear and gear door install. My question is: what gear door rams would you all use and gear valve?
Thanks for the help, great thread.

Steve
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Old 05-18-2010, 11:22 PM
  #1317
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Default RE: Another Skymaster Viper

Steve,

Finding gear door rams would be relatively easy. Finding gear would be something different. Tom Cook retracts with Digitec struts would get you part way but I'm not sure what to use for brakes. I bought the bare kit and have been piecing it together. I did buy the gear with it. It's nicely made stuff and as long as it stands up, I think it was worth getting.

Nice jet though, overall you won't be dissapointed with the airframe. Just be prepared to fix a few things to get it right.

PaulD
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Old 05-19-2010, 01:57 AM
  #1318
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Default RE: Another Skymaster Viper

Hi Dunc, did you post any pics of your flights? notice you haven't been on the other forum lately, did they rumble you?[sm=lol.gif]

I've been pushing H to get on with his one, he's softening
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Old 05-19-2010, 02:03 AM
  #1319
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Default RE: Another Skymaster Viper

Steve,
after I changed the tubing to 4 mm to the gears, I have had no problems retracting them (but do remember to slow down when retracting, otherwise they won't lock!)
The doors seems to be closed on mine in flight, and that is even after I cut the rectangles in the airbrakes to get rid of the vacuum inside the fuselage
I'm pretty sure that Skymaster changed the "attack" point for the door cyllinders, on the "older" Vipers we have here, they were placed at a less than optimum position than they are on the "newer" ones we have
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Old 05-19-2010, 03:13 AM
  #1320
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Default RE: Another Skymaster Viper

Hi Vince

There are some flying pics a page or two back, near the top of the page i think. Yes you need to get Henry to finish his viper, he had it 3 months before i did !!!! oh yea jiveturkey was killed off, but he'll be back with another ip addy

Carsten

mine has no problems locking the gear, without coming off the throttle after take off and that was with standard BMV airline. I did however treat all the air cylinders to a bit of BVM thin O lube to make sure all the seals where seated and sealing properly.
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Old 05-19-2010, 05:58 AM
  #1321
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Default RE: Another Skymaster Viper

Here are the pics of my gear door mod. I tried to make it look like part of the original former, i did have a pic of the brack et i made, but must of deleted it, so i have attached a really bad sketch of what it basically looks like.

Duncan





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Old 05-19-2010, 09:55 AM
  #1322
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Default RE: Another Skymaster Viper


Quote:
ORIGINAL: PaulD

Steve,

Finding gear door rams would be relatively easy. Finding gear would be something different. Tom Cook retracts with Digitec struts would get you part way but I'm not sure what to use for brakes. I bought the bare kit and have been piecing it together. I did buy the gear with it. It's nicely made stuff and as long as it stands up, I think it was worth getting.

Nice jet though, overall you won't be dissapointed with the airframe. Just be prepared to fix a few things to get it right.

PaulD
I plan on using the gear that SM has, just want a better ram and any tricks that work for you guys.

Steve
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Old 05-19-2010, 12:45 PM
  #1323
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Default RE: Another Skymaster Viper

Quote:
ORIGINAL: Duncan

Here are the pics of my gear door mod. I tried to make it look like part of the original former, i did have a pic of the brack et i made, but must of deleted it, so i have attached a really bad sketch of what it basically looks like.

Duncan


Duncan, Fantastic!!! what RAMS are you using?

Many thanks,

Gonzalo

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Old 05-20-2010, 09:27 AM
  #1324
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Default RE: Another Skymaster Viper

Back to the collapsing canopy thing.

Has anyone ever looked at the intake ducts. I was staring at mine last night while doing some work on the plane. There is a significant reduction in area from the intakes on either side of the cockpit to the point where the two ducts merge. At that point the 2 airstreams are hitting each other at almost 180 deg and the cross section area looks to be reduced to about half. Even with a bypass, there could still be a problem getting enough airflow esp at low airspeeds and sudden increase in turbine speed.

There is a small NACA duct on the right side of the forward fuse. Has anyone opened this one up to provide some airflow to the canopy area? It's not very big but might make a difference.

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Old 05-20-2010, 12:17 PM
  #1325
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Default RE: Another Skymaster Viper


Quote:
ORIGINAL: gonzalom


Duncan, Fantastic!!! what RAMS are you using?

Many thanks,

Gonzalo

No worries Gonzalo. They are standard BVM 2" units http://alshobbies.com/shop/lookupstock.php?pc=6332

Duncan
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