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Re: Extended gear first impressions

Posted: Sun Sep 12, 2021 11:29 am
by Andy Young
I must admit, the question of axle position intrigues me, so I’ve begun digging a little deeper.

A few initial findings:

I’ve just compared a stock gear leg to an extended gear leg. The angle of the front tube to the top anchor points appears to be identical: about 90°. While I did not check with precision measuring tools, any angle difference large enough to reposition the axle 3” forward seems like it would be obvious.

Airframes is closed today, but the information on their website states that the 4” extended gear gives an additional 3” of clearance. No mention of a change to axle position. I’ll give them a shout next week and ask.

It did occur to me that the longer gear WOULD move the axle forward relative to the ground, while in the THREE-POINT position (resting on the ground). But this is not the proper position for weighing the airplane and calculating CG.

One step in the weighing/CG determination process is measuring the position of the axle relative to the datum. I once measured mine while it still had stock-length gear, and it was 2.50” on the left side, and 2.25” on the right. Has anyone done that measurement with extended gear? Could you share that here?

Re: Extended gear first impressions

Posted: Sun Sep 12, 2021 1:00 pm
by FARMAULE
Andy Young, that all makes perfect since. I did in fact measure mine (don’t recall it being a big adjustment to the paperwork, definitely not 3 inches) but since sold that airplane. Maybe the new owner will chime in with the numbers. In a spring geared M7 now. The gear moving fwd in a 3 point attitude is most likely what Wup’s BCP post is referring too. At the end of the day it should be a bonus in ground handling if it is moved fwd shouldn’t it? Or is my mind backwards on that? Also would make the tail heavier which maybe negates that. All I know is I love Maules and have since my first flight in one in 2011, great aircraft.

Re: Extended gear first impressions

Posted: Mon Sep 13, 2021 2:37 pm
by andy
Sounds like the axle is at the same station in level attitude but the gear is 2 lbs heavier than the stock Maule gear so W&B recalculation is needed. The main advantage of the extended gear is more prop tip clearance in level attitude, which allows for a longer prop and more thrust. It also gives more positive angle of attack in 3-point attitude as you accelerate for takeoff until the tail comes up. That would argue for taking off in a 3-point attitude but then the drag of the tail wheel on the ground would slow it down a bit. I've tried taking off in both a 3-point attitude and lifting the tail when the airspeed comes alive. It doesn't seem like there's any difference in takeoff distance so I lift the tail when the airspeed comes alive in order to see in front of me better and save the tail wheel some beating.

Re: Extended gear first impressions

Posted: Mon Sep 13, 2021 2:53 pm
by ajak
For whatever it's worth, here are some measurements I took when transitioning from stock Maule gear to the Airframes extended gear a while back, with no other changes at the time. All measurements are with 29" Bushwheels.

Width- between inner sidewalls:
Stock: 61.2"
Extended: 65.5"

Height- prop blade clearance (81" McCauley, as measured in 3-point attitude):
Stock: 22.8"
Extended: 28.3"

Dist, fwd horiz stab edge to back of tire:
Stock: 138.1"L/138.2"R
Extended: 140.0"L/140.3"R

One can infer from that data that moving from stock gear to the extended gear (again, with 29" Bushwheels):
(1) Extended the width between tires by about 4"
(2) Increased prop clearance by 5-1/2"
(3) Moved the gear forward by about 2"- meaning that CG should be affected accordingly.

Re: Extended gear first impressions

Posted: Mon Sep 13, 2021 4:47 pm
by riverbuggy
The main wheels didn't move forward; they moved down thus increasing your measurement by 2". If the aircraft were leveled, and the same measuring points were plotted on the ground the measurement would be the same with stock gear or extended gear