Landing Gear Attachment to Fuselage Question

[acrojohn]

I have seen quite a few S1 fuselage pictures, but the one pictured here seems a bit unique. Can anyone explain the origin of this mod and offer ideas as to how the cowl lower half would fit?

John

 

[racegunz]

In the plans updates and in the news letters, there are references to adding "wedges" to the landing gear to align it with the longerons, supposed to help handling on the roll-out ect. This just looks like a stout way to do just that.

 

[Raceair]

These particular wedges are tailored for the Grove gear clamps , I believe. The gear wedges are supposed to put the leading edge of the gear 90 degrees from the top longeron. Wedges on Sonerai 1's are a must in my opinion, for ground handling benefits, and drag reduction.
The lower cowl still clears everything, as, in that area, it is a couple inches below the lower longerons…..Ed

 

[racegunz]

Ed how would that help in "drag reduction" if the cowl covers the attachment area?

 

[Raceair]

It helps in Drag Reduction, because the gear legs are slicing thru the air at a '0' lift line. If you bolt the gear directly to the bottom longerons at the angle it is at, the inner sides of the gear slabs will be pushing air…..Ed

 

[racegunz]

Okay had to go look to see what you meant, indeed in the stock form they will be deflected a bit from the direction of flight.

 

[acrojohn]

I do appreciate this near real-time support answering my questions as I come up to speed on this project. My confidence in the quality of the project is quite high. The original builder appears to have done a very good job. It will be enjoyable finishing the project and getting it into the air.
Thanks again,

John

 

[acrojohn]

I have been studying this issue on the project I'm considering acquiring and I can't see how the gear is going to fit without extensive rework. Based on lateral and vertical dimensions between the cowl and the longerons (provided by helpful folks here) it doesn't appear the gear spring will even fit inside the cowl. It might be possible to get rid of the thick Grove block bracket and install radius plates to raise the gear attach point some, but I don't think that will be enough. If the wedge was cut off and the longerons cleaned up to convert the gear back to the original configuration, the bolt bushings would not be at the optimum attach angle, and still the forward bolt bushing and plate would be positioned well outside the longeron. If there is just a 1/4" gap here between the side of the cowl and the longeron an unusually large fairing would be required to make it fit and clean it up.
Has anyone got some pictures of a clean wedge installation (with and without the cowl)?
Would it be possible to obtain a copy of the wedge modification drawings and description?

Thanks
John

 

[Raceair]

John, I have been looking at your pictures of the gear clamps and wedge weldment, and I think that if you get rid of the clamps, and leave the weldment, you might be able to just put the gear in place, and fashion 1/4" thick steel straps to hold the gear up. The 'radiused' clamps are 'optimum', but the radius is not totally required, just preferred. A compromise like I am describing would raise the gear up a bit, and possibly clear most of the cowl.
I am rebuilding a Mong right now with 900 hours on it. Undoubtedly several hundred landings.. It has a steel spring gear, and is attached with plates that are 5/16" thick, 1 1/2" wide, and maybe 6" long. The spring gear strap attach has been used on homebuilts from the sixties, on up thru the 90's when someone realized that the radiuses clamps would be Better, and better they are, but thinner, flat plats have worked fine for decades…Ed F.

 

[acrojohn]

I respect all inputs, but I have just received the dimensions from the original builder that indicate that the gear could only be made to fit inside the cowl with little if any clearance. Even without the radius bars the gear is still going to deflect with little or no place to go. The gear spring in this project is the older 1/2 inch spring so the deflection will be greater than the five eighths spring.

IMHO radius bars are a requirement. I've heard about too many longeron cracks. While they were on larger aircraft - they had heavier parts. It is a matter of scale. See the attached notice from Grove. One can be frugal or hope for the best landings all the time, but it just takes one bad one and a little radius would have saved a lot of aggravation. This is a cheap quick fix and the bar/plate is the same size as the quarter of an inch steel strap suggested. The 6061 aluminum radius bar is plenty strong enough for my 1650 GW Acrosport II. The Sonerai longeron doubler provides strength and a radiused surface on top of the spring. Without the wedges, I think it would be possible to get away with only one lower radius plate per side. The flat surface wedge and the height of this particular wedge gets in the way of that option. I am really cautious of modifications and free style fabrication outside of the plans on critical structures. I'd sure like to hear from anyone who has successfully installed wedges and see some pictures or drawings. I need to decide how much of this I'm willing to redo.
Thanks

John

 

[Raceair]

John, I have another alternative that will work, and I will snail mail you some sketches……Ed