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Old Mar 27, 2012, 02:37 PM
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Quote:
Originally Posted by SU-4ever View Post
No, I don't agree.

The momentum is created by force per distance to attatchment point of the working arm, not to the CG. Lowering the mount towards the floor (With the plane sitting wheels down, of course) means keeping the exact same working arm. So, if I just happen to design a mount that has more area (For example, glueing ply wood on the foam walls instead of the ceiling) I will also be able to conduct greater landing forces without breaking.

I've drawn a scheme to show what I'm trying to tell, maybe I'm not explaining myself clear enough

Cheers!
You like formula's so;
A fulcrum, Distance (in or cm) x force (oz/in or g/cm) = Distance (in or cm) x force (oz/in or g/cm)

The mass and position of the model hasn't changed. So the further the distance the greater the force. You are correct when your perspective is isolated to only the same strut and retract and box but relative to the entire structure, now your build up and the foam frame has to be able to support more force simply because the wheel is further from the models center of mass.

Try it by exaggeration; extend the mount to 10 feet. Now attach the same strut assembley to it. Is it seeing the same force relative to the model?
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Old Mar 27, 2012, 02:52 PM
You are a "go" for reentry
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OK. I guess you tried it and it fits cause that was your earlier concern. The Tamjet struts sit like a straight post with no weight but articulate like the trailing link under load. So that why I mentioned those in particular. Still looking for a source for everyones reference.

Quote:
Originally Posted by SU-4ever
An alternative to the main struts are the Eurofighter trailing links with 50-55 mm diameter wheel
I forgot the use of the shock arm either short spring with factory arm or replacing the factory arm with a spring tube shock to dampen the rotational loads.

Quote:
Originally Posted by Maxthrottle View Post
DamonH: Spot on.

That mod list a page or so back are not a must do in most cases. It depends more on the mission, pilot and runway.

Next short runway mod recommendation I had was add a rocket motor to the raydome tail with Antaeus' chute ahead.

But also for consideration re weight, the model is supposed to be 2.7kg and that is about 200g above the common retract rating so with an additional 200g+ of battery weight with models coming in at 3.1-3.2Kg may be a stresser.

Pilot technique and runway conditions are going to play into putting any of us probably one or two mistakes from having gear issues.

So summary;
If you're comfortable with a slight aft CG (165-170) it can work to your advantage.

Standard 50m of pavement is likely a non issue for anyone except maybe those hauling above a ~800g battery.

Grass needs a nose gear mount beef up and a regular check of the mains toeing out. A potential remedy is change up the Trunnions to PZ metal, and repeating faults may consider increasing the shaft rod to 5mm or change mains to something like the tamjet trailing link strut.

Short runways may need increasing the nose strut length and if possible flaps. And for braking Chute and or Air brakes.
Increase to strut length may need reinforcement to the gear mount.

Did I miss anything to categorizing these in their own boxes?
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Last edited by Maxthrottle; Mar 27, 2012 at 03:18 PM.
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Old Mar 27, 2012, 03:06 PM
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[QUOTE=Maxthrottle;21158281]DamonH: Spot on.

Next short runway mod recommendation I had was add a rocket motor to the raydome tail with Antaeus' chute ahead.

LOL...hmmmm, would a bottlle rocket add much thrust?
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Old Mar 27, 2012, 03:08 PM
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Originally Posted by RCflyerCT View Post
Thanks...I will check. Also, it had never happened until I switched batteries to the GensAce 5300 (prior I was using a Sky Lipo 4400 and had no problems with it). I have 3 of the new GensAce, and flew all 3 of them, so I do not think it was a specific battery issue but not sure. I did notice my battery to ESC connector was RED HOT (and it was never before with the Sky Lipos 4400 - and I really flew the same was as before). ANy thoughts on that?

Thanks,

Wes
You may have what V8 described then. A cold solder connection thats adding a lot more resistance in the connector and may be on the verge if not already desoldering. Thus the pulse.

Regarding various batteries it could be... while the motor only demands what it can use, they can use themselves to self destructive burn up. So those extra amps from the battery is only limited by the ESC. The Sky lipo may have a greater Volt sag or other that is just not giving the motor as much as the next battery. If the connector is a fault and more current passes the more it shows itself to be the problem child.

Now that all being speculation, you could tell by adding a watt meter and see the through put for each battery. We know that some who have flown 4500 55C have available 247.5 amps. None that I know of have said the ESC cut out so either they are not red lining it for long or the motor is not demanding much over ~55amps for any length of time.
Either way I'd have a good look at the connectors like V8 described.
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Old Mar 27, 2012, 03:28 PM
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Quote:
Originally Posted by v8truckin View Post
hoping you'll post some pics would like to know how u got those euro struts to tuck into the retract bay?
Hopefully this weekend!

They enter just fine, the wheel stays out a bit, but since it's less diameter it's not that ugly when seen from far...
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Old Mar 27, 2012, 03:33 PM
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Hey the big wheel sticking out as is, is an eyesore that I have to live with. I am so tempted to try a Russian rotating retract.
Anyways, actually Jandro you may be interested in these;

Tam Jets Strut Trailing Offset Right 100mm. This is just a sample from a vendor and in not way is to support or promote said vendor.

If the SU-35 is;

Strut:
Nose Gear Strut and Wheel Height_155mm_, Wheel Dia. _45mm_
Main Gear Strut and Wheel Height_120mm_, Wheel Dia._65mm_

The Tamjets will accommodate Wheel Dimensions:
Offset strut : 2" - 2 1/4" (50 - 57mm)
Straight strut: 2 1/2" - 3" (63 - 75mm)

So the offset strut with a 57mm wheel would bring you to 157mm on the nose.
The Mains would be 150mm which is 30mm longer but you could replace the spring so that its softer and thus sits lower when on the ground but goes straight when retracted... ah but then the wheel would be 30mm further forward.... which isn't so bad since it still would tuck in the well.
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Old Mar 27, 2012, 04:03 PM
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Max those are some very nice looking struts. Might have to get me a set when they come out just to fiddle with (not that I need em), very nice indeed. Thanks for the link
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Old Mar 27, 2012, 04:06 PM
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Quote:
Originally Posted by v8truckin View Post
Max those are some very nice looking struts. Might have to get me a set when they come out just to fiddle with (not that I need em), very nice indeed. Thanks for the link
I'm trying to find what the length of the ones for the Habu are cause they may be exactly the right size but they are not offset to prevent the potential toeing that Jandro isn't fond of.
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Old Mar 27, 2012, 05:35 PM
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Wow, thanks Max!

Didn't knew them, I think you just hit the sweet spot!

Apart from nice looking and well-finished they seem pretty affordable!

Now that I've installed the Eurofighter struts (Which I had as spare when I acquired my second Euro) I will leave them installed on The SU but keep an eye on these for future EDF's to come (I've yet to build a Hobby Topgun L-39 for FPV purposes and didn't like the stock struts...)

Cheers!
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Old Mar 27, 2012, 06:12 PM
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USA, CA, San Francisco
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Quote:
Originally Posted by Maxthrottle View Post
Hey the big wheel sticking out as is, is an eyesore that I have to live with. I am so tempted to try a Russian rotating retract.
Anyways, actually Jandro you may be interested in these;

Tam Jets Strut Trailing Offset Right 100mm. This is just a sample from a vendor and in not way is to support or promote said vendor.

If the SU-35 is;

Strut:
Nose Gear Strut and Wheel Height_155mm_, Wheel Dia. _45mm_
Main Gear Strut and Wheel Height_120mm_, Wheel Dia._65mm_

The Tamjets will accommodate Wheel Dimensions:
Offset strut : 2" - 2 1/4" (50 - 57mm)
Straight strut: 2 1/2" - 3" (63 - 75mm)

So the offset strut with a 57mm wheel would bring you to 157mm on the nose.
The Mains would be 150mm which is 30mm longer but you could replace the spring so that its softer and thus sits lower when on the ground but goes straight when retracted... ah but then the wheel would be 30mm further forward.... which isn't so bad since it still would tuck in the well.
Woah. Those look amazing and $45 is very affordable. Awesome find!!!
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Old Mar 27, 2012, 06:43 PM
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United States, CA, Lancaster
Joined Feb 2012
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Quote:
Originally Posted by Maxthrottle View Post
Hey the big wheel sticking out as is, is an eyesore that I have to live with. I am so tempted to try a Russian rotating retract.
Anyways, actually Jandro you may be interested in these;

Tam Jets Strut Trailing Offset Right 100mm. This is just a sample from a vendor and in not way is to support or promote said vendor.

If the SU-35 is;

Strut:
Nose Gear Strut and Wheel Height_155mm_, Wheel Dia. _45mm_
Main Gear Strut and Wheel Height_120mm_, Wheel Dia._65mm_

The Tamjets will accommodate Wheel Dimensions:
Offset strut : 2" - 2 1/4" (50 - 57mm)
Straight strut: 2 1/2" - 3" (63 - 75mm)

So the offset strut with a 57mm wheel would bring you to 157mm on the nose.
The Mains would be 150mm which is 30mm longer but you could replace the spring so that its softer and thus sits lower when on the ground but goes straight when retracted... ah but then the wheel would be 30mm further forward.... which isn't so bad since it still would tuck in the well.
SO MAx, how would these gear retract with the wheel wells they way they are stock? I don't have the model yet.. its here tomorrow, but it looks like the wheels just slide in the holes.. would one have to cut the airframe to get the gear up? I do like the spring action... seem pretty good idea for any surface..dampening the shock loads..
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Old Mar 27, 2012, 07:08 PM
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United States, CA, Sunnyvale
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And Tam is local to us!! I might bring the struts down and compare them.

Quote:
Originally Posted by tmsn View Post
Woah. Those look amazing and $45 is very affordable. Awesome find!!!
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Old Mar 27, 2012, 07:18 PM
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Now this is how it's done ...

Very Nice RC SU-35 Landing (0 min 28 sec)
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Old Mar 27, 2012, 07:27 PM
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That was his 1st SU35 that he crashed when he had the ailerons reversed after switching to a new radio. He just maidened his 2nd but I think that one is down as well.

Quote:
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Now this is how it's done ...

http://www.youtube.com/watch?v=TH4cYvGAt_I
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Old Mar 27, 2012, 07:28 PM
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Maxthrottle's Avatar
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Quote:
Originally Posted by vhuang168 View Post
And Tam is local to us!! I might bring the struts down and compare them.
That would be good for all of us. If they tend to be long I'm curious how short you could go cutting them down some and going shorter on the spring.

But not certain if I'm seeing the entire selection from the vendors and interwebs.

The tall narrow wheel is an advantage on grass so if while your there you could beg them to do a special order for the SU-35 like they did for the Habu

Ed since these are straight legs but may be a little long it would be like have what is there stock with a longer strut. The offset struts might recess these closer up against the duct but till someone has them in hand, its hard to say. I'm not sure of the dimension options at this time.
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