Nose Gear Lessons Learned

[MacCool]

I installed a -21 from the top (for reasons that I mentioned earlier in this thread) with a washer under the head, and two under the nut, and I did not pound out the firewall.

You just add the washer and the nut as you are tapping the bolt through the leg. IOW... you can't just drive the bolt in and expect the washer and nut to go on without interference from the FW.

To remove the existing bolt from the top, I clamped vise grips onto the head and tapped the grips with a hammer.

Yes. We pushed the bolt in from the top until just a few threads stuck out the bottom. I stuck the two washers over those threads with a glob of grease, then we held the nut against those threads with a 12" hemostat while using a gear wrench to turn the bolt head. After the threads were engaged with the nut, we switched the hemostat for a wrench on the nut and tightened, thus drawing the bolt in the rest of the way until flush and the nut was tight. The bolt was longer than a 20, so the dent we pounded in the firewall was necessary. The close-tolerance bolt was long enough that it allowed the shoulder of the bolt to bear completely on both holes in the strut socket no more than the thickness of the two washers. The project got a workout today with a 60-kid Young Eagles event. Re-checking for wobble afterward was gratifying.

 

[Dr_Dave_MT]

Yes. We pushed the bolt in from the top until just a few threads stuck out the bottom. I stuck the two washers over those threads with a glob of grease, then we held the nut against those threads with a 12" hemostat while using a gear wrench to turn the bolt head. After the threads were engaged with the nut, we switched the hemostat for a wrench on the nut and tightened, thus drawing the bolt in the rest of the way until flush and the nut was tight. The bolt was longer than a 20, so the dent we pounded in the firewall was necessary. The close-tolerance bolt was long enough that it allowed the shoulder of the bolt to bear completely on both holes in the strut socket no more than the thickness of the two washers. The project got a workout today with a 60-kid Young Eagles event. Re-checking for wobble afterward was gratifying.

Uffda! That’s a lot of eaglets flown! How many aircraft? I did 5x in one day, that was a lot for the little 9r.

 

[MacCool]

Uffda! That’s a lot of eaglets flown! How many aircraft? I did 5x in one day, that was a lot for the little 9r.

Uff Da indeed . Must be some Norwegian in you Dr. Dave.

We had 7 airplanes...an Archer, couple of 172's, couple of light-sports, a Carbon CubX on floats (!), and me. I'm a member of two EAA chapters that fly Young Eagles, about 20 miles apart (I live 10 miles from each). Each chapter does at least one YE event per year, but sometimes we'll fly additional out of the smaller aiports around here as part of a fly-in or promotional event. 40-60 kids kids is about normal here. One event, we had 91. We each generally fly all 5 slots. I have finally pretty much nailed down an effective hot-start routine for my airplane. I've always been interested that so many of these kids want to fly in my RV. I guess I shouldn't be surprised since I'd rather fly in an RV over a Piper or Cessna too. In both of these EAA chapters, I not only have the only RV, I have the only Experimental airplane as well.

 

[banzai37]

My 7A's nosegear has rotational play (AFTT:1000 hrs). I've removed the bolt and found the hole in the engine mount to be oval - 0.328 wide and 0.320 tall. I'm about to use a reamer and an oversize bolt. How do I make sure the reamer is inserted exactly aligned with the existing hole? I will get the recommended piloted reamer, and was thinking about inserting the nosegear so the pilot has something to ride against in the engine mount. Should I make a guide instead?

 

[Carl Froehlich]

Here are posts about an RV-10 nose gear issue that is not covered in a SB.

But, the Van's updated engine mount and nose gear is a good upgrade to older RV-10's that may be showing the same problem.

RV-10 Engine Mount / Nose gear leg play

During the condition inspection I hoisted the nose using an engine hoist to work on the nose wheel and gave the original 2012 build nose gear leg a wiggle test. The nose gear leg moved left and right about an inch and wiggled up and down a few inches even though elastomeric pads were making...

vansairforce.net

 

[lr172]

My 7A's nosegear has rotational play (AFTT:1000 hrs). I've removed the bolt and found the hole in the engine mount to be oval - 0.328 wide and 0.320 tall. I'm about to use a reamer and an oversize bolt. How do I make sure the reamer is inserted exactly aligned with the existing hole? I will get the recommended piloted reamer, and was thinking about inserting the nosegear so the pilot has something to ride against in the engine mount. Should I make a guide instead?

what size bolt are you going to?

 

[Finley Atherton]

My 7A's nosegear has rotational play (AFTT:1000 hrs). I've removed the bolt and found the hole in the engine mount to be oval - 0.328 wide and 0.320 tall. I'm about to use a reamer and an oversize bolt. How do I make sure the reamer is inserted exactly aligned with the existing hole? I will get the recommended piloted reamer, and was thinking about inserting the nosegear so the pilot has something to ride against in the engine mount. Should I make a guide instead?

This is how I did it.

Alternative to reaming nose gear bolt?

I have been reading the threads regarding the replacement of the nose gear bolt with close tolerance bolts or taper pins. I don't think I actually came across a single report of someone doing this successfully with the engine and mount still on the plane. Just throwing this idea out there. What...

vansairforce.net

 

[banzai37]

This is how I did it.

Alternative to reaming nose gear bolt?

I have been reading the threads regarding the replacement of the nose gear bolt with close tolerance bolts or taper pins. I don't think I actually came across a single report of someone doing this successfully with the engine and mount still on the plane. Just throwing this idea out there. What...

vansairforce.net

Thank you. I plan to go to the NAS6605-26X bolt (1/64 oversize). The method you described is how I was considering to do it - using the nosegear leg to support the pilot as I ream the first surface of the mount. Your multi-step process is even more careful. Was your reamer a square shank? Do you recall the part number? I believe the reamer recommended in the original post from this thread is a straight shank (straight-shank PPR-.3261).

 

[lr172]

Thank you. I plan to go to the NAS6605-26X bolt (1/64 oversize). The method you described is how I was considering to do it - using the nosegear leg to support the pilot as I ream the first surface of the mount. Your multi-step process is even more careful. Was your reamer a square shank? Do you recall the part number? I believe the reamer recommended in the original post from this thread is a straight shank (straight-shank PPR-.3261).

Given the ovalled hole, you need to lock the gear leg in place, otherwise the reamer can wander. Also, due to the curved surface, it doesn’t engage most of the hole initially. The pilot locks the cutting line only, but doesn’t prevent the reamer from following what it wants, as the pilot is in a moveable object. If it wanders, you may not be well aligned with the bottom hole and that results in a non circle given the zero margin. Given that you have no margin (new bolt is .016 larger than original & hole is .017 larger) that could be an issue.

 

[Finley Atherton]

Thank you. I plan to go to the NAS6605-26X bolt (1/64 oversize). The method you described is how I was considering to do it - using the nosegear leg to support the pilot as I ream the first surface of the mount. Your multi-step process is even more careful. Was your reamer a square shank? Do you recall the part number? I believe the reamer recommended in the original post from this thread is a straight shank (straight-shank PPR-.3261).

This shows the reamer and bolt I used. The reamer is threaded. Can’t remember how I attached it to the ratchet socket drive.

Alternative to reaming nose gear bolt?

I have been reading the threads regarding the replacement of the nose gear bolt with close tolerance bolts or taper pins. I don't think I actually came across a single report of someone doing this successfully with the engine and mount still on the plane. Just throwing this idea out there. What...

vansairforce.net

Thank you. I plan to go to the NAS6605-26X bolt (1/64 oversize). The method you described is how I was considering to do it - using the nosegear leg to support the pilot as I ream the first surface of the mount. Your multi-step process is even more careful. Was your reamer a square shank? Do you recall the part number? I believe the reamer recommended in the original post from this thread is a straight shank (straight-shank PPR-.3261).

 

[banzai37]

Given the ovalled hole, you need to lock the gear leg in place, otherwise the reamer can wander. Also, due to the curved surface, it doesn’t engage most of the hole initially. The pilot locks the cutting line only, but doesn’t prevent the reamer from following what it wants, as the pilot is in a moveable object. If it wanders, you may not be well aligned with the bottom hole and that results in a non circle given the zero margin. Given that you have no margin (new bolt is .016 larger than original & hole is .017 larger) that could be an issue.

>>you need to lock the gear leg in place
Roger.

>>due to the curved surface, it doesn’t engage most of the hole initially
Great point.