Primarily for general aviation discussion, but other aviation topics are also welcome.
#1780402
EssJay wrote:He's dropped a few off the cuff comments in a few videos about being able to lock them in the up position when in flight.

I missed such comments, but what advantage would that give? Surely the same amount of stuff is still hanging out in the breeze. Reducing rotational inertia in lateral control, maybe?
#1780411
rf3flyer wrote:
EssJay wrote:He's dropped a few off the cuff comments in a few videos about being able to lock them in the up position when in flight.

I missed such comments, but what advantage would that give? Surely the same amount of stuff is still hanging out in the breeze. Reducing rotational inertia in lateral control, maybe?
Who knows but I'd guess he knows what he is doing better than maybe you or I do when it comes to designing aircraft at the more extreme end of the light aircraft scene.

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#1780437
rf3flyer wrote:
EssJay wrote:He's dropped a few off the cuff comments in a few videos about being able to lock them in the up position when in flight.

I missed such comments, but what advantage would that give? Surely the same amount of stuff is still hanging out in the breeze. Reducing rotational inertia in lateral control, maybe?


Yes, in the up position it is more wing and less fin.
#1780444
I missed such comments, but what advantage would that give? Surely the same amount of stuff is still hanging out in the breeze. Reducing rotational inertia in lateral control, maybe?


My thinking on his gear wings is twofold:

First, if he is able to use the 'special project' with Kings, that he mentioned, to 'retract' the gear upwards then clearly the wings become much more useful wings, akin to a canard. As we all know, tailplanes are wasters of energy because it is (basically) 'negative lift', whereas canards are 'positive lift'. So, his gear wings become useful providers of lift and reduce the wastage down the back.

Second, the extended gear wings will, in conjunction with the 'body flap', produce a very nice cushion of air beneath his machine and that will be extremely useful when it comes to the ultra-slow flight that he wants in order to get his landings rolls incredibly short.

I love the man's ability to think about 20 steps ahead of what he wants to achieve with any part. For instance, I'd cut out a door panel and then realise I needed something on the back for it to close smoothly etc. He just sees the problems way before they happen. Truly a great workman :thumleft:
#1780446
I'd be very interested to know how long the design process for Scrappy has been. The impression given is it's all been very quick, but I don't think it can have been.

Unless I've missed something, he's mentioned nothing about the wings. Curious to know when they'll be discussed / introduced. It's not like they're going to be stock Carbon Cubs wings :D
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By xtophe
#1780450
PaulSS wrote:Second, the extended gear wings will, in conjunction with the 'body flap', produce a very nice cushion of air beneath his machine and that will be extremely useful when it comes to the ultra-slow flight that he wants in order to get his landings rolls incredibly short.


But for the landing, it needs the gears in the low position i.e. the wing producing less lift. So it would need the mechanism to adjust the gear position to be very fast. And dumping lift in the flare or held-off would just make the aircraft drop.
By Hooligan
#1780452
TheKentishFledgling wrote:I'd be very interested to know how long the design process for Scrappy has been. The impression given is it's all been very quick, but I don't think it can have been.

Unless I've missed something, he's mentioned nothing about the wings. Curious to know when they'll be discussed / introduced. It's not like they're going to be stock Carbon Cubs wings :D


I can't recall him mentioning the wings either - my guess is either a "OMG, what did I forget" moment or "here's one I made earlier". :lol:

I certainly enjoy the videos, takes me all my get up and go to paint a length of skirting...

Back to sleep... :D
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By PaulSS
#1780463
But for the landing, it needs the gears in the low position i.e. the wing producing less lift.


I think at the landing speeds we're talking about the loss of lift from the gear wings would be more than made up by the air 'cushion' he is seeking to build by damming the air between the wings and body flap.

Maybe he'll design it so the gear lowers as the body flap extends beyond a certain point.
#1780466
G-BLEW wrote:Where does the spring element come from on the suspension?
They are oleo-pneumatic (oil and gas filled). The gas, usually nitrogen, is the spring and the oil is for the dampening.

I am second guessing him here but I would say there is an accumulator and the valving is controlled electronically in a similar way to how modern adaptive car suspension works. The accumulator will allow for extra oil to be moved to and from the shock housing. Weather there is a second accumulator for the nitrogen, I'm not sure but I would suggest there isn't and the 4 or 500psi in normal operations would be boosted whilst the extra oil is in the shock housing.


I don't think it's intention is for lift in the approach but more lift in the departure and cruise phase. The rate of climb out of Draco is approx 4000ft/min at 30 degrees and that is a much heavier airframe with 'only' another 150 or so horsepower. Maybe he's aiming for 5000ft/min!

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Last edited by EssJay on Tue Jun 30, 2020 10:41 am, edited 2 times in total.
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By G-BLEW
#1780477
EssJay wrote:They are oleo-pneumatic (oil and gas filled). The gas, usually nitrogen, is the spring and the oil is for the dampening.


Thanks, just watched the 'movement' part of the video (29 minutes in) again, and I'd missed his comment about the shocks not being charged.

Ian
#1780489
EssJay wrote:Who knows but I'd guess he knows what he is doing better than maybe you or I do when it comes to designing aircraft at the more extreme end of the light aircraft scene.

No question about that but that need not stop the likes of you or I speculating about the perceived benefits.

@patowalker & @PaulSS Yeah I get the additional lift that his gear 'wings' will offer but wouldn't that benefit be had in the air rather than at STOL?
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By G-BLEW
#1780503
proteus wrote:Did he not float the idea on Draco that he wanted to somehow lock the shocks down and have an electronic release to spring the aircraft into the air for take off? I wonder if the trick shocks are something similar.


Imagine enough of a power/weight ratio to be able to spring up and fly away in a gentle breeze (without turning the aircraft sideways)

Ian