RE: Another Skymaster Viper
 

Check with Anton, but i think 1.1mm is the thicker wing tube. The thin ones were 0.6mm extruded jobbies

RE: Another Skymaster Viper
 

Hi Duncan

Thanks. I know the replaced new one, as discussed, has 1.1. mm, but even with reinforcements afaik.
My one is a "simple" tube. Therefore i ask for that.

RE: Another Skymaster Viper
 

My replacement from the factory was 1.1 and a simple tube with no reinforcements in the centre.

RE: Another Skymaster Viper
 

Yes, unfortunately the new one with 1,1 mm is a "simple" tube. Lucky who got the first one with internal reinforcements... However I think also the new one is strong enough if you fly normally and I never heard about problem with it. Instead a friend of mine had a problem with the vertical fin and lost the viper [:@]. If you did a removable fin modification check it very well before flight expecially the carbon tube beacuse it enters in the fin only 3/4 cm ! and expecially if you don't place the servo inside the fin (in this case the fin become stronger). I'm thinking about what to do... perhaps I'm going to take away the carbon tube and place a longer one.[&:]
Ali, if you are reading us, please let us know what you think about it.
Thanks

Alessandro

RE: Another Skymaster Viper
 

Hi Murray

Thanks for the Information. Hope the tube will be strong enough to endure my first jet landing http://www.rcuniverse.com/forum/js/f...ssed_smile.gif

Kind Regards
Rainer

RE: Another Skymaster Viper
 

Hi Allessandro

Thanks for the Information. Hope the tube will be strong enough to endure my first jet landing [img]images/smiley/msn/embaressed_smile.gif[/img]
The CarbonFibre in my Fin is approx. 4 cm long. Should be long enough, but even i will insert a metal plate with a screw to fix the Fin in fuselage for a higher certainty.

Kind Regards
Rainer

RE: Another Skymaster Viper
 

Hi
for sure the new tube is strong enough. Have more then 30 flights with this new tube w.o. inner reinforce !
Brg
Fritz/Switzerland

RE: Another Skymaster Viper
 

I have 2 flights on the new tube only and no problem so far.

RE: Another Skymaster Viper
 

I forgot to say I have 6 flights with one "not so soft" landing... :D I had almost a stall at 30 cm from the ground because I was landing too far from me and I didn't realize I was too slow in a very long runway and I broke the pin of front gear and the wooden base of the right wing gear but the tube it's still perfect!
I used the carbon fiber reinforcement from digiteh on the wings (that didn't broke) so I think for this reason I didn't have any more damage...
However I would have preferred the first tube![:o]
Alessandro

RE: Another Skymaster Viper
 

I have never flown a viper or a hawk on the new tube. Only ever the old tube with the material in the middle. If anyone is bending one of these tubes, they must be putting more pressure on the wings than me ( Which when you think about the full power knife edge, pushed circuit I do, surprises me ) Then maybe they are lucky the tube bet... Before something in the wing bent.
I never once had a issue with the carbon rudder tube. Even when I lost most of my fin due to rudder flutter on the original demo model.
Regards Al

RE: Another Skymaster Viper
 

<span class="long_text" id="result_box"><span title="" style="">Hello everyone ...

</span><span title="" style="">I am Nicol&ograve; from Rome (Italy) ..

</span><span title="" style="">I remained speechless when it happened in the air that you see on attached image, I think there are serious problems on the rudder of the new Viper far more than the bayonet .... there is

not even a thread of glue and </span><span title="">balsa wood inside the fiberglass is mounted upside down, pay attention to the bayonets of carbon ...

</span><span title="">a greeting to all</span></span>

RE: Another Skymaster Viper
 

Thanks Ali now I feel much more confortable :)

About the rudder, my friend didn't have a problem with a bent of the carbon tube but exactly with a flutter while flying stable with a jetcat 160. We think is a flutter caused by the carbon tube that is inserted only 3,5 cm inside the rudder and almost without glue. He didn't put the servo inside the rudder but on the fuz, so the "walls" of the rudder aren't so compact like in mine (and most of us) that have the servo inside. A strange thing is that I tried to pull the tube with some pressure and it come away from rudder due to lack of glue, very strange isn't it? I don't know what to do but I'm thinking to replace the tube....[&:]
What is your opinion and what happened to you?
Thanks!
Alessandro

P.S.: always sorry for my english[:o]

RE: Another Skymaster Viper
 

As you understand the plane I'm speaking of is exactly this one of Nicolò....
Nicolò, tremendous pictures to see...[X(]

Ciao
Alessandro

RE: Another Skymaster Viper
 

<span class="long_text" id="result_box"><span title="" style="">Hello Alessandrohttp://www.rcuniverse.com/forum/js/f...ular_smile.gif
</span><span title="" style="">I think the Chinese models are good models, but shortly after their completion, for me, when firms enter into production of their products begin to have serious problems,http://www.rcuniverse.com/forum/js/f...humbs_down.gif
which is why we should be careful ...http://www.rcuniverse.com/forum/js/f...ngry_smile.gif

</span><span title="">Ciao Nicol&ograve;</span></span>

RE: Another Skymaster Viper
 

I am so sorry to see the loss of your viper.
I can not for sure tell you why that Viper lost its fin, but if its flutter then what I can tell you is that all the cases of flutter that I have seen to date have come from the rudder itself fluttering, leading to the fin fluttering. It happened to me on my very first viper.
I see that there is a very long servo arm fitted to the rudder servo. Which servo was it used on the rudder?
Regards Al

RE: Another Skymaster Viper
 

Nocolo,

Sad indeed. And beleive me we are sad. We would like to get behind the cause if yoo can help.

My experince is the same as Ali. Any structure will fail with flutter. Just the other day 2 full size pilots in SA were killed when aileron flutter and the wings departed from airplane in the air. So it does not matter if all ribs and more carbon tubes - the end result will be fin fracture or complete rudder departure.

In the manual stated the slop in surface will cause flutter. Also stated that the hinge gap needs to be cut so that rudder leading edge aome as close as possible to fin trailing edge. In my years i have seen the pin hinges with no support from fin to ruddder. Most do this to get max deflection - but this is bad. Some have solved the problem but glueing a sleeve around the hinge to support it. All this is well documented on RCU.

Please send us some detail pictures of your hinges and control horns and linkage. Also some video if you have...

I am not saying this was problem - i am just talking out of experience. All SM Viper Fins are build the same since the innitial prototype fin departure couple of years back. We have flown Viper with P200 with no problem. Ali do a complete knive edge circuit with no problem. And we all know how he can fly:)

Hope we can resolve this problem asap.

Regars

Morne

RE: Another Skymaster Viper
 

Just want to thank all of you for the great info on the Viper jet. I should be receiving mine in about a month or so. We have a very interesting guy in are club, his name is Alan Brown, chief design engineer for the Lockheed F-117. He has helped me with a lot of my 40% stuff in the past so I am going to put him to work on the Viper jet and see what aerodynamic fixes/changes he can come up with. I will post as we come up with changes.

Steve

http://www.lockheedmartin.com/capabi...lth/index.html

RE: Another Skymaster Viper
 

<span class="medium_text" id="result_box"><span title="" style="">Hello Ali
</span><span title="" style="">the servo is mounted as a Jr. 8711 said the Skymaster, and I can assure you that there was absolutely vibration on the rudder ... </span><span title="">while I was flying exploded as seen in photo

Regards Nicol&ograve;
</span></span>

RE: Another Skymaster Viper
 

<span class="long_text" id="result_box"><span title="">Hello Morne
</span><span title="" style="">Thanks for your interest
</span><span title="">There are many years flying with the jet models, and like all I did wrong in the past that have enhanced and enriched my experience.
</span><span title="">as I wrote to Anton and Jhon video of what I have not because I was alone, I try to aagiungere some photos that confirm what I say ... the explosion of the central part of the rudder exclude your ideas ....
</span><span title="">IN THE RUDDER IS NOT THE GLUE.http://www.rcuniverse.com/forum/js/f.../sad_smile.gif

</span><span title="">Regards Nicol&ograve;
</span></span>

RE: Another Skymaster Viper
 

Hey Steve, Congrats on the Viper! Where will you be flying it?

RE: Another Skymaster Viper
 

I will be flying at the Salinas field, approx. 470' paved. I may put some of Henry's speed brakes on the Viper, I think it will help with the shorter strip, keep my spool-up time shorted if needed.

RE: Another Skymaster Viper
 

Hi Nicolo,

Mate, sorry for your loss.

I think we should see your problem together with a host of other issues - such as the cracking canopies and the vent holes that many guys have had to cut into their planes. The Viper seems to have an extrodinary high internal pressure problem, which on the one hand is sucking in the canopies and on the other, blowing the fin skin of the plane. This coupled with the by-pass not being fitted, the interior not being glued to the canopy frame (to seal the canopy area) and very small outlet area around the exit of the pipe (so the pressure now goes up into the fin) - all makes for an implosion/explosion waiting to happen. Adding to this the glue problem, it make for some serious re-thinking required by both SM and modellers planning their installations.

The glue problem is something that has manifested itself accross many of the SM models (I had the same thing on a small SM F-86, where there was absolutely no glue on the main undercarriage mounts) and many other modellers have had similar issues as reported on RCU.

Given that SM is such a prominent manufacturer and having the very knowledgable ear of many extremely good jet pilots (Ali M, Bob V etc comes to mind) surely they can get these problems sorted before we, the modellers, are put in an R&D position.

Just my2 cents.

Cheers

Jan

RE: Another Skymaster Viper
 

Hi Nicolo

We just had a meeting with our fiberglass airframe supplier.We agreed on requesting you to send back tail for investigation.Can you please send us back the tail for close check here?

Best regards

John
Skymaster

RE: Another Skymaster Viper
 

Jan

For the few guys that have had a problem with internal pressure, there are many more that haven't had any problems. Mine is running a bypassed 160, the gear doors stay shut and the canopy doesn't try to implode (something that should be impossible on a well bypassed setup). Now i would of said that it could be i just fly my viper softly, but Ali has as many flights on it as i do, so i know that's not the case. It's been put through his normal schedule several times and hasn't missed a beat.

There are so many vipers out there now and yes some have suffered failures, how many have been caused by a manufacturing error and how many by the builders/pilots error is anyones guess.


Duncan

RE: Another Skymaster Viper
 

Duncan,

Thanks for agreeing with me. My point being - a bypass installation is paramount to this plane and the rest is up to proper installation and flying. However, we cannot get away from the fact that SM are missing glueing various aspects of various models in their range and that is not our (modellers) problem - it is SM's problem to resolve.

Cheers

Jan