Nosewheel assembly - Considerations with heavy blades

Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
3,524
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
Greetings again.

I am in the market for purchasing a complete nosewheel assembly for my GyroBee. Several manufacturers offer parts of different configurations, but one important consideration is the hefty weight of the Gyro-Tech rotor. It has been discussed in another thread that the GyroBee was intended for lighter blades so I won't go into that here. The major change I've made over the stock design is a robust suspension on the mains (ATV shock/dampers). I am interested in following suit with a shock absorbing nosewheel to minimize loads on the mast if terrain is less than ideal.

I have put a message to Trenna of Sport Copter to inquire if it is possible to fit their Lightning nosewheel to a square tube keel. Am waiting to hear back.

My question to the Forum: Is there a drawback to a shock dampened nosewheel that I am not thinking of? In other words, is there a hidden danger in going this route? Some oscillation that could build and make things worse? The goal is a free castering design with simple scrub brake or small disc. I also know that Denis of Gyro Technique makes one with a centering spring. But before considering all the options, I wanted to consult the resident experts here. I would be grateful for any input on the subject. Thank you kindly.

Brian Jackson
 
Greetings again.

I am in the market for purchasing a complete nosewheel assembly for my GyroBee. Several manufacturers offer parts of different configurations, but one important consideration is the hefty weight of the Gyro-Tech rotor. It has been discussed in another thread that the GyroBee was intended for lighter blades so I won't go into that here. The major change I've made over the stock design is a robust suspension on the mains (ATV shock/dampers). I am interested in following suit with a shock absorbing nosewheel to minimize loads on the mast if terrain is less than ideal.

I have put a message to Trenna of Sport Copter to inquire if it is possible to fit their Lightning nosewheel to a square tube keel. Am waiting to hear back.

My question to the Forum: Is there a drawback to a shock dampened nosewheel that I am not thinking of? In other words, is there a hidden danger in going this route? Some oscillation that could build and make things worse? The goal is a free castering design with simple scrub brake or small disc. I also know that Denis of Gyro Technique makes one with a centering spring. But before considering all the options, I wanted to consult the resident experts here. I would be grateful for any input on the subject. Thank you kindly.

Brian Jackson
Hi Brian,
There was two very interesting threads "Back Country Gyro Ops. Equipment, mods, techniques" and "Gyrpoplanes Vs Bushplanes" back in February. There were some great info and pictures from Jungleman re nosewheel modifications to Magni and Sportscopter gyros for rough field operations. Might be of interest? Something to think about is the load on the nosewheel and the load spec for the tyre you plan to use. Best regards, John H
 
Not just heavy blades.

What was interesting was how it highlighted the problems that can occur with nose-wheels that are perhaps to small/thin in relation to the mains when operating in soft conditions.

A point that I might bring up with Denis at some later stage.

Brian I sense that perhaps both you and I may be at a stage where we are hesitant to change what has been done.
 
Thank you gentlemen.

John, I am reading through those threads now. Quite lengthy. Thank you for the thread titles, as the search function on RWF is... wanting.

Resasi, good points and observation. I seem to recall quite a few gyros with large mains and narrow nosewheel, wondering how its thinness might tend to slice into soft, bumpy ground instead of rolling over it. But there are gaping holes in my knowledge of gyros that have yet to be filled.

I have the Azusa wheels and tires pictured below:

NOSEWHEEL:
azusa nose gear tire.png

MAINS:
azusa main gear tire.png

Side note: GyroJake recommended the round profiles over the square/flat due to a noticeable decrease in drag.

If I go with a manufacturer's nosewheel assembly, it may necessarily include the wheel and tire if the fork width is sized for that. If I fabricate a stock Bee nosewheel fork will I wish later that I'd done a shock absorbing design instead? If the mass of the rotor is being jostled around by 3 points of contact with the ground, it would seem reasonable to want all 3 to be dampened. Especially considering the long moment arm of a Bee mast and the added mass of a composite rotor.

I'm also trying to have the ship nearing completion by Thanksgiving in preparation for its first inspection by a well respected member of this forum. And I confess to 'builder fatigue' after months and years of weekends of construction. I like the idea of a pre-manufactured item provided the design and quality are stellar. There's also a lot more going on with a nosewheel than meets the eye (anti-shimmy, trail, etc.) that I don't want to assume I can design one without flaw.

Anyway, I'm getting long-winded again so it's time for me to shut up and keep learning.
 
Brian, remember that a Bensen-configuration gyro such as the 'Bee is really a cross between a tri-gear aircraft and a tailwheel aircraft. The mains aren't that much behind the CG and, as a result, the load on the nosewheel is light -- typically a few dozen pounds. The mains do most of the weight-bearing work. So a cushioned nosewheel is more of a luxury than a necessity... and it adds weight.

OTOH, a nosewheel that resist digging-in is a boon -- the usual tipover scenario in any tricycle-geared vehicle with one wheel in front is sideways-and-forward. Been there, done that, etc. Tires of larger diameter and width resist digging in better than teeny and/or skinny ones.

The only exception to my "who needs it" opinion is regarding long-travel mains. For example, a Butterfly has over a foot of main-gear travel, and was marketed to do aggressive "stop-and-drop" landings. Some of them have a fixed nosewheel, though, so, when you first touch down with the mains extended, the nosewheel is still a foot off the ground. This, in turn, forces the pilot to hold back stick as the gear settles in, lest the gyro tip forward and then over. But holding back stick in that situation also invites a tip-over if there's a cross-wind. So it's better with that kind of gear to have a long-travel nose-gear leg, IMHO.

Otherwise, I'd save the weight and expense.
 
http://www.aircreationusa.com/linked/plans_nom_gb_racer_447_march_2003.pdf For anyone interested the drawings of an Aircreation Fun Racer trike shows the nose gear arrangement. I had one of these trikes and it was very stable on the ground. I tried to buy tis assembly from Aircreation but it is not currently available.. But notice it does have shocks on the front wheel.
 
Brian, remember that a Bensen-configuration gyro such as the 'Bee is really a cross between a tri-gear aircraft and a tailwheel aircraft. The mains aren't that much behind the CG and, as a result, the load on the nosewheel is light -- typically a few dozen pounds. The mains do most of the weight-bearing work. So a cushioned nosewheel is more of a luxury than a necessity... and it adds weight.

OTOH, a nosewheel that resist digging-in is a boon -- the usual tipover scenario in any tricycle-geared vehicle with one wheel in front is sideways-and-forward. Been there, done that, etc. Tires of larger diameter and width resist digging in better than teeny and/or skinny ones.

The only exception to my "who needs it" opinion is regarding long-travel mains. For example, a Butterfly has over a foot of main-gear travel, and was marketed to do aggressive "stop-and-drop" landings. Some of them have a fixed nosewheel, though, so, when you first touch down with the mains extended, the nosewheel is still a foot off the ground. This, in turn, forces the pilot to hold back stick as the gear settles in, lest the gyro tip forward and then over. But holding back stick in that situation also invites a tip-over if there's a cross-wind. So it's better with that kind of gear to have a long-travel nose-gear leg, IMHO.

Otherwise, I'd save the weight and expense.
Dough, has somebody tried ( on "pushers") some kind of tailwheel configuration with "smartly located" mains? Thanks,
P.S. Dough and Wolfi, I did not get any response to your questions from POLO Boris yet.
Busy or pissed at questioning his authority? Hope it is not the latter.
 
Georgi: I think I've seen one such craft, but long ago. There are unique problems with handling a tailwheel gyro -- you must be very careful to keep the stick centered while your main wheels are on the ground. If you move it to the side, you can start a ground loop that will be difficult to stop. This is in addition to the usual ground-loop issues with tailwheel gear.

The other challenge with a pusher taildragger gyro is the height of the thrustline. The engine must quite high for the prop to clear the tail tube/beam. Then, to preserve CLT, the pilot must sit REALLY far above the ground. A boarding ladder or steps will be necessary.

Have a look at the old Buhl pusher -- especially the altitude of the cockpit pod. Nosebleed seats!

I hope Boris isn't offended at our questions.
 
Brian, remember that a Bensen-configuration gyro such as the 'Bee is really a cross between a tri-gear aircraft and a tailwheel aircraft. The mains aren't that much behind the CG and, as a result, the load on the nosewheel is light -- typically a few dozen pounds. The mains do most of the weight-bearing work. So a cushioned nosewheel is more of a luxury than a necessity... and it adds weight.

OTOH, a nosewheel that resist digging-in is a boon -- the usual tipover scenario in any tricycle-geared vehicle with one wheel in front is sideways-and-forward. Been there, done that, etc. Tires of larger diameter and width resist digging in better than teeny and/or skinny ones.

The only exception to my "who needs it" opinion is regarding long-travel mains. For example, a Butterfly has over a foot of main-gear travel, and was marketed to do aggressive "stop-and-drop" landings. Some of them have a fixed nosewheel, though, so, when you first touch down with the mains extended, the nosewheel is still a foot off the ground. This, in turn, forces the pilot to hold back stick as the gear settles in, lest the gyro tip forward and then over. But holding back stick in that situation also invites a tip-over if there's a cross-wind. So it's better with that kind of gear to have a long-travel nose-gear leg, IMHO.

Otherwise, I'd save the weight and expense.
Thank you, Doug. As always, very good points to consider. Studied all the postings that John H directed me to (Thank you, John!) and have a new appreciation for good ground handling. Trenna and Jim of Sport Copter contacted me regarding my initial questions to say their nosewheel assembly can be used on the GyroBee provided their bearing block and dampening discs are used. They are putting together a quote. I'm sure it's expensive but won't be worrying about cost when barreling down a runway or soft field.

Weight is the bigger consideration, so would like to compare theirs against other, simpler types. Have been very weight-conscious with anything below the CG. No decision made yet, just weighing my options, so to speak.

Also Doug, thank you for the insights regarding other gear types and their dynamic behaviors. Makes perfect sense and a great physics lesson. Will post as I learn more.
 
Weight is always a concern, but you're making a Bee and the more pressing concerns are going to be how much room for a front fork and wheel do you have? If you have adjustment possible with your main gear setup then it's pretty easy, but if you don't, the Bee has less room for a front wheel and tire than most gyros. How high off the floor is the bottom of the front keel tube now? Can you change the main gear to raise (or lower) that height? Probably the most space efficient and lightest solution is the Brock/Bensen fork and wheel setups.
 
BTW Brian, Are you coming to Mentone this year? Will you be bringing your build?
 
IIRC the gyrobee was configured for fairly heavy blades. Improves the thrustline/VCG alignment.
Someone will correct me if in error on this.
 
YEARS ago, I designed a castering dampened nose wheel for my SOMA gyroplane, it worked great.
 
I tried searching but cant find it, I would assume it was 2005-2006 when I posted the thread here.
 
Weight is always a concern, but you're making a Bee and the more pressing concerns are going to be how much room for a front fork and wheel do you have? If you have adjustment possible with your main gear setup then it's pretty easy, but if you don't, the Bee has less room for a front wheel and tire than most gyros. How high off the floor is the bottom of the front keel tube now? Can you change the main gear to raise (or lower) that height? Probably the most space efficient and lightest solution is the Brock/Bensen fork and wheel setups.
Thank you, gentlemen.

John,

Yes, I have intentionally left the mains' diagonal strut tubes uncut so that their lengths could be coordinated with the final keel height, which is dependent on the nosewheel configuration. No re-working required. Jim Vanek said their nosewheel assembly will fit the 'Bee, and I believe uses the same tire. Will know more later today. The photo linked above from the 'Crescendo Build' thread was not representative of the final keel height. Once the target height is determined via nosewheel installation the mains' axles will be bent accordingly so that they and the mains' lower struts are fixed at the appropriate angles. Will share more pics and details as they come.
 
Sport Copter nosewheel assembly on the way! Decided to go that route for a few reasons mentioned earlier. Could have saved a metric ton (or two) of cash going DIY, but it's a very light, robust system with pivoting rubber suspension. After some Q&A with me they are machining a version of their Lightning bearing block to fit the 2X2x.125 tubing. That's some Class-A customer service. What a joy doing business with them, and Trenna is awesome.

Not sure how long this will take to fab & ship but have plenty to keep me busy until then. Have a lot of progress pics still to post on the Crescendo Build thread... sorry, have been neglecting that. Any spare time has been consumed by building. Cheers.
 
Rotor Ute nosewheel . All chromoly .
 

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