Carden Ultimate

[TheTank]

	Quote: Originally Posted by Danny Baker
	It's freshman physics to say that a swept back gear puts more stress on the forward two gear bolts than normal or swept forward gear during a bouncy landing. Dan Baker Team Carden

That is correct... yet you have failed to answer the question: what does it matter if you land properly and have a gear plate that is designed correctly to handle the stress? As for the bolts, it is also "freshman physics" that the tensil strength on a set of steel bolts is probably a bit higher than that of the wood the gear is mounted to... I used to harrier land my 31 pound, 35% Ultimate, and never had any bolts break, thats for sure, and I believe they were 8-32s. The gear plate had a small piece of aluminum angle tying it in to the motorbox, additional stress issue solved. Seems like a pretty simple issue to me.

[jmiracle]

I think there's more stress on those bolts than most people realize. I agree with you Tank that you'd think the strength of a set of steel bolts is much greater than that of a block of maple wood.....however, a couple years ago, I had an ignition battery go bad in my 35% Carden in a hover......belly flopped it from about 20ft. All 4 of those steel bolts (8-32's!) sheared clean off without so much as a scratch on the wood. I backed out the broken bolts and spun news ones into the old holes.....went on to fly the plane for 2 more seasons without a single issue after that.

[SleepyC]

I remember that Jason, I was like NOOOOOOOOOOOOOOOOOOO it's dead... OH CRAP.
And when we got to the plane, the gear had simply pulled off and a tiny bit of balsa was crushed.
You had it fixed in I think 7 days. Cardens are seriously strong airplanes!

[jmiracle]

yup....that was the day that really sold me on how well these planes are built. I only had to replace the belly pan because the gear rolled back and crushed the first few inches.....that and i had the typical "dimples" in the bottoms of the wings where the wheel pants smacked 'em.

I ordered the replacement belly pan from Carden on Monday, had it on Wednesday, and had the plane repaired and ready to fly by the weekend. I couldn't have asked for an easier repair.

[tonyc9075]

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[MikeC3D]

[Bdegan]

A rearward swept gear looks awesome. But the one thing that happens is the wheels or axles end up being very close to the balance point of the aircraft.
For those that have to fly off grass, and not all grass fields are putting greens. It would cause it to be very sensitive to nosing over.
A straight gear helps with this problem, although it doesn't look as good.
My suggestion would be to mount the swept gear as far forward as would be allowed and remain within the IMAC 10% to scale rule.

[Wojcigitty]

	Quote: Originally Posted by TheTank
	That is correct... yet you have failed to answer the question: what does it matter if you land properly and have a gear plate that is designed correctly to handle the stress? As for the bolts, it is also "freshman physics" that the tensil strength on a set of steel bolts is probably a bit higher than that of the wood the gear is mounted to... I used to harrier land my 31 pound, 35% Ultimate, and never had any bolts break, thats for sure, and I believe they were 8-32s. The gear plate had a small piece of aluminum angle tying it in to the motorbox, additional stress issue solved. Seems like a pretty simple issue to me.

It is certainly possible to design a gear plate to handle the stresses involved with swept landing gear. With a correctly designed gear plate, the gear should bend before the gear plate rips out (in my opinion).

However, as has been pointed out before, swept landing gear causes more stress than right angle or forward swept gear. This is because with right angle gear, all or most landing forces push directly into the bottom of the fuselage. With swept gear, the front gear bolts are loaded in tension, and the rear gear bolts are not loaded at all. There is a moment (twisting force) about the gear plate that tries to bend the gear backwards.

So with swept gear, there is additional force to deal with. This means that you need to make the structure beefier, which means more material, which means more weight.

It comes down to this: swept gear looks badass, and it's used on the full scale version for whatever reason. But on models, right angle or forward-swept gear is a better choice because it means less stress on the gear plate, allowing for a lighter gear plate.

I'm sure the guys at Carden are still trying to find an acceptable compromise between scale looks and structural integrity/weight, and it's certainly a difficult challenge.

The airplane looks awesome, by the way...I want one.

[MikeC3D]

Ok, another month has gone by, any more news to report ? Any pics yet?

[Danny Baker]

Mr Mike: The 20-300 goes in the air tomorrow, Thursday, at high noon. The plane is done and the engine has been ran up. The principals are in route to the meeting field as we speek. As promised, I will be there to take it all in. I will take pictures. As of now there is only one picture of it completed, and I've not got permission to post. Full details when I return.

Dan Baker
Team Carden

[rcflyguy]

Sweet! Can't wait!

[reyn3545]

[T. Bob]

Found a picture of it!

Looks pretty good!

[cjcyclesrc]

	Quote: Originally Posted by T. Bob
	Found a picture of it! Looks pretty good!

[craig77]

Awesome!moving house and will be setting up my work bench waiting for this baby!