View Full Version : Question For You Rocket Guys

Steve Barnes
12-01-2010, 02:51 PM
I have Harmon's titanium gear. I have wood stiffners made for Van's gear legs. What attach method to the titanium works the best. Open to any other ideas for stiffning the gear a bit.

Steve Barnes "The Builders Coach"

12-01-2010, 04:29 PM
use Proseal to bond the wood to the leg, then up and back down with a roll of 4" fiberglass tape. With epoxy of course.

Master Designs
12-01-2010, 05:09 PM
Are these legs still running $1,700 each from Harmon? :eek:

12-02-2010, 11:05 AM
Bob is right -- Proseal to glue 'em to the Ti legs.
IMPORTANT: Wrap the glass at 30 deg angles -- use a large marker to draw the 30 deg lines on your stiffeners (one layer wraps upward; the second layer should wrap opposite) so you can get the angles close to this. Use 2 crossing layers of 9 oz tape -- width does not matter: just be sure to have 2 layers crossing over the entire assembly.
The wood is there as a spacer (more or less) for the fiberglass wrap. The wood/composite assembly is more of a damper, not a stiffener -- it does strengthen the leg a bit, but not much. I have used ash, oak, and settled on poplar, as it is easiest to machine to shape. The type of wood made no difference in performance, but the angle of the wrap did.
Apply the wood and glass while the ship is suspended, so the legs are straight. You will see the glass pop loose from the Ti when you let the ship down -- no worries.
Carry on!

Steve Barnes
12-02-2010, 08:23 PM
This is the information I was looking for. These titanium gear make every landing seem perfect. I'm not looking for a stiffer gear. Just a more stable gear. Any chance that we will see that side by side in the next few years.

Steve Barnes

12-03-2010, 09:12 AM
This is the information I was looking for. These titanium gear make every landing seem perfect. I'm not looking for a stiffer gear. Just a more stable gear. Any chance that we will see that side by side in the next few years.

Steve Barnes

Nothing is for sure, but I'm not working on a SBS version. I AM working on new production kits....based on the Evo.

Don't ask questions just yet - let me get a but further along so I can give more complete answers.

Carry on!

12-03-2010, 12:34 PM
Don't ask questions just yet

Come on Mark some of us will die from the suspense.

Spill the beans now.

Mike S
12-03-2010, 12:45 PM
Don't ask questions just yet -

You really do want to get flooded with questions, dont you???:D

Ever seen a sigh saying "wet paint, dont touch"

12-03-2010, 12:53 PM
Hey Milt:

Anything I can (reliably) tell you has already been posted in the Rocket section of the VAF site. I'm outta here tomorrow for 7 days at latitude 15N -- be back on the 13th. Search thru the data, and you'll be pretty much up to date, but with the knowledge that I'm moving closer to production.

I gotta get to that final design, laid out so many years ago, and see it fly. After that, I'll take a break.

Caveat: one saying keeps running thru my brain: "Be careful what you wish for -- you might get it!":eek:

Carry on!

PS http://www.vansairforce.com/community/showthread.php?t=58766&highlight=wing&page=2

12-03-2010, 10:21 PM
Mark told me that he was close to finalizing the drawings for an experimental Do-335 using the evo wing, tricycle gear, and two 800hp aluminum block V-8s. He said it was the only way he could beat Tom Martin.

Here's a photo: http://www.wwiivehicles.com/germany/aircraft/fighters/dornier-do-335-pfiel/dornier-do-335-pfiel-03.jpg

Sorry, it's late and I couldn't resist. (But what a cool homebuilt it would be!)

12-05-2010, 08:23 AM

I left my HR2 legs "naked" sans wooden stiffeners. Why? 1400 hours in my short and later long-geared RV4 experience on grass strips. Steve Wittman designed the tubular spring steel gear to flex on less than smooth surfaces. The wood stiffeners really transfer the load from the leg to the mount sockets on rough surfaces. My strip seriously qualifies as a rough surface for my HR2 and 60% of my landings are off pavement (1000 hours worth). So if you travel off road, consider leaving them off. Even on pavement I don't get "the shakes" on slowdown on my HR2 I believe partly due to my balancing of my wheel pants and my larger tires. Your call...


Steve Barnes
12-05-2010, 12:16 PM
Thanks Smokey. I didn't think of the transfer of load. I don't want to shed my Titanium legs like one unnamed pilot did.


Tom Martin
12-05-2010, 01:23 PM
It might be worth a call to John Harmon regarding this issue. The F1 gear legs are larger in diameter then some of the early HRII gear legs and with a stiffer engine mount a different harmonic was noted with the F1 legs. Wood stiffeners helped to greatly reduce this harmonic.
I did not have wood stiffeners on my HRII legs and encountered no issues. I do have then on my F1 and feel that they are necessary with that gear.
A few years about there was a "service bulletin" issued by John Harmon regarding a machining issue on a batch of gear legs. You might check to see if your legs are in that batch. I do believe that later HRII legs increased in diameter and I do not know if that increased size resulted in the harmonic issue that the stiffer F1 legs encountered.

Norman CYYJ
12-13-2010, 09:49 AM
Tom do ski's work on your rocket and what kind of speeds can you obtain. lol