3399 Nose Gear

[superuser]

08-10-2008, 04:25 AM

Mike | 3399 Nose Gear

Does anyone have any info on how they "beefed" up the nose gear compartment for water landings..Picts..? Thnx

[superuser]

09-29-2008, 04:35 AM

Seapilot1 | 3439

Hi Mike; I used my experience with Lakes, which in the early years had lots of problems with the nose gear doors folding inward and tearing the bulkhead or sticking in the jammed up position. I will post some pictures on how to solve that problem, if that is what you are talking about. I've encountered some 2.5 ft waves and some great porposes to prove that they hold up. Ron Broyles 415-492-9134

09-29-2008, 04:38 AM

Mike | 3441

Hey Ron,

Hope all is well with you and yours.... Thanks for the info. I have already placed a horizontal stop above the tire. Feel free to post the picts or email them to me.

09-11-2009, 07:01 AM

Mike

A few weeks ago I had the chance to test the new bar that was placed above the tire to stop the tire from going thru the compartment hatch. The bar did its job however the hatch cover ended up in the water anyway. I missed the very tight measurement between the top rear of the NLG steering actuator and the hatch cover. Unfortunately there is about.....no.... room, so when the gear is up the actuator rests against the hatch. Needless to say, if the tire hits the cross bar (about 1/4") the hatch will pop off. After reading a bunch of posts it became very clear that that the NLG doors need to be "beefed" up or I need to make better water landings. Anyway, I decided to redesign the doors and have recently finished installing new aluminum doors, brackets, and stops. Hitting the water is like hitting the concrete. The glass doors seen to be very weak area. Water is whole different "animal".

09-23-2009, 01:17 PM

Dean | nose gear actuator attach plate

the attach bolts pulled thru the nose bulkhead because the washers on the opposite side of the bulkhead from the mounting bracket were the same size as the bolt head. These washers should be at least 1" dia to give a larger bearing surface. The stress on the bracket is on the bolt closest to the pilot and pulls the bracket towards the passinger side (to right) when gear is retracted. You will not get am "up" nose light. When gear is down, sstress is releaved pushing the bracket back into position so you can't see that the

bolt has pulled thru, or that the outboart attach tab on the actuator has broken off the bent the inboard tab. You can go several landings before the entire assembly pulls loose and you could end up with a jamed up-down unlocked nose gear. I jacked the plane and found the problem before total failure.

09-23-2009, 06:48 PM

Fred Lohr

tell ya what...speaking from experience even larger washers are not really enough. I really put my nose gear to the test when i used to pull it around with a tractor here on the farm taking it back and forth to the ramp, not to mention beating up the gear on a turf strip. I reccomend using a piece of 1/8 stainless steel plate cut to a pattern that gives a nice wide surface area. make a matching plate for the inside. drill the two holes,roughen up the surface and bond it to the fiberglass panel with epoxy as you install the bolts.the plate on the inside will prevent the bracket from gradually digging into the inner side of the fiberglass panel with repeated stress. that "digging in" of the bracket is very hard to see on inspection. with backing plates, problem solved. backing plates are also a big plus where the rod for the nose gear arm pivots thru the bulkheads.

09-23-2009, 07:15 PM

Mike

A couple of issues......

1- The nose door blew off because of the tolerance between the cover and the top of the actuator. The 2 arms that hold the cover on were intact.

2- Are you saying that the bolt that holds the hydraulic actuator in the nose will eventually pull thru the fiberglass..?

I had the entire NLG system disassembled last week. The yoke had several cracks. Needless to say I inspected and repaired the yoke. The gear doors were changed to 1/8” aluminum.

09-24-2009, 11:54 AM

Fred Lohr

well, yes if you abuse the gear like i do. The actuator is bolted to a bracket and the bracket is held to the left nose gear bulkhead by two An4 bolts. The bolts and bracket get some forces transmitted to them somehow and can begin to work the bolts thru the bulkhead and/or cause the bracket to dig into the bulkhead on the inside. Easily solved with a stainless steel backing plate on each side of that bulkhead to support bracket and bolts.

On another note... a wise seawind pilot whose name escapes me told me to attach a strap to my deck lid cover so that you can retrieve it when you eventually make one of those mistakes on the water and blow it off the top. I lost mine when it happened to me and I had to make a new one.

also be aware that there are two styles of nose gear actuator, one has small easily broken tabs where it bolts to the bracket and the newer one has much beefier tabs which do not break. Once that bracket starts tilting as Dean describes, it will stress the small tabs and they break.

[superuser]

09-24-2009, 09:13 PM

Mike

Quote:

Originally Posted by Fred Lohr View Post

well, yes if you abuse the gear like i do. The actuator is bolted to a bracket and the bracket is held to the left nose gear bulkhead by two An4 bolts. The bolts and bracket get some forces transmitted to them somehow and can begin to work the bolts thru the bulkhead and/or cause the bracket to dig into the bulkhead on the inside. Easily solved with a stainless steel backing plate on each side of that bulkhead to support bracket and bolts.


On another note... a wise seawind pilot whose name escapes me told me to attach a strap to my deck lid cover so that you can retrieve it when you eventually make one of those mistakes on the water and blow it off the top. I lost mine when it happened to me and I had to make a new one.

also be aware that there are two styles of nose gear actuator, one has small easily broken tabs where it bolts to the bracket and the newer one has much beefier tabs which do not break. Once that bracket starts tilting as Dean describes, it will stress the small tabs and they break.


Ok - got it. I will be doing an annual this weekend so i will check the fiberglass. Stainless sounds like a good idea! Funny you should mention the strap...I was thiking the same last night. I would like to see how you took care of all this at the splashin.....see you all there

11-07-2009, 01:23 PM

Mike | Follow up .....Nose compartment hatch poping off

When the seawind nose hits the water hard, the nose compartment cover will tend to pop off the plane.

Why..?

1- Water pushes up on the gear doors and in turn pushes the tire up hitting the hatch and therefore popping the hatch off.
2- Some one also mentioned that the rapid compression of the air within the compartment will also pop the hatch off.
3- The other reason is that the hydraulic nose wheel cylinder rests on the bottom of the hatch when the hatch is closed and the gear is up. Any movement of the gear upwards will pop the hatch off.

I have placed a bar across the top of the tire and re-enforced the side walls. I have also made up new gear doors out of 1/8 aluminum. Instead of the fiberglass “L” brackets I lined the inside with aluminum bar stock to keep the doors from folding up into the compartment. The bar and bar stock should work well for a massive upward thrust of the tire however; if the tire does compress the nose wheel actuator will move up and pop the hatch off.

Would placing a spring loaded door in the hatch directly above the nose wheel actuator take care of The Hanger & #3 above?

Have I missed anything? Is this a good solution other than not hitting hard……?

PS - I have cad drawings if anyone is interested...



07-26-2010, 04:55 PM

Dean | nose fork separation at spindel attach (4 bolts)

hI GUYS--LOST THE nose wheel on landing--no we haven't been hitting the nose hard. Seems the torque transmitted to the front two attach bolts when the nose contacts the runway stresses these and causes them fo fail. On inspection I found there's only about 1/2" of thread in the triangular block and appear to be machine (fine). Part needs to be modified as all stress is transmitted to the front two bolts on about a 7" arm. I have the longer hyd shaft and am looking for this part and a replacement nose fork--anyone know where I might find them??. I will probably machine the block and shaft and when I do I'll change the fork angle slightly the bring the point of contact of the tire to runway just slightly forward. Going the reno air races this year--wonder in they have an amphibian class?? If anyone else is going, give me a call so we can meet--907 244 8661