Retractable Gear question

[CyberSushi]

Has anyone considered or investigated the possibility of using motorcycle front forks as an alternative retractable gear setup?

 

The front forks of a new Yamaha R1 or the new Aprilia are light, strong and should be able to do the job. Of course, some mods are required all over the place ...

 

Any ideas?

[Jon Matcho]

Not that I know of, but could possibly work somehow. Would need a lot of design work to make it happen though, and in my opinion not worth the time and expense.

[CyberSushi]

My catch is that the cost of landing the Infinity retracts here in South Africa is probably going to cost me in the region of R60,000, which is approximately $10,000 - double the price of the gear. It's ridiculously expensive to get parts shipped out here.

 

Seeing as I would like retractables, I'm kinda forced towards having to design my own, or mod another aircraft's retracts to fit the Cozy. Bike shocks appealed to me 'cos I believe they work on the same principle as the Infinity's gear, and it'll cost me about R12,000, or $2,000 to get them modded to fit.

 

Anyhow, if anyone does have any ideas, feel free to fire them my way.

 

Thanks!

[j hinchliffe]

Seems a huge cost for shipping to south Africa. A contact of mine ships auto engines between there and the US for far less. Have you had a fixed quotation?

[CyberSushi]

It's not so much the shipping, it's more the Import Duty and the VAT (Value Added Tax) I would have to pay to clear it through Customs.

 

I'm not sure why I have to pay VAT on the product. I can understand the Import Duties, but at the end of the day, shipping costs, plus taxes and duties will probably add about 60 - 80% of the original cost.

 

I can find out from Infinity what their shipping costs would be, but trying to get an answer from the SA Customs people is nigh impossible. I'll see what I can do.

[j hinchliffe]

Not sure on the legalities in S A but whenever i 'acquire' something from the US , i have it clearly stated on the packaging and any paperwork that it is a free commercial sample. Never paid any duties.

[CyberSushi]

See ... that's why you ask questions on the forums. Then you get good suggestions like that.

 

I'm gonna give it a try.

 

Thanks!

[j hinchliffe]

Something small first to 'test' the system. Your tax rules may be different to the uk.

[j hinchliffe]

'Gift' usually works too. Make sure that no bills, invoices etc are included with your parcel. Have them mailed seperate.

[Marc Zeitlin]

'Gift' usually works too. Make sure that no bills, invoices etc are included with your parcel. Have them mailed seperate.

Maybe discussions on how to break the laws of your individual countries are best left to private emails?

[j hinchliffe]

Point taken.

[Spodman]

...using motorcycle front forks as an alternative retractable gear setup

I am assuming you would be rigging one fork as an oleo. You'll need some sort of hinge link to keep the wheel straight and a much more robust spring. Save even more money and don't make it retractable. I assume you are talking about mains here.

 

Maybe discussions on how to break the laws of your individual countries are best best deleted by those who posted their intentions. In Australia pilots using the www.pprune.com forums have been prosecuted on what they said there (allegedly).

[tonyslongez]

Cybersushi

 

I have a really neat idea that I'm implementing on my long Ez using a GSXR 750 fork for a steerable nosegear. I can send you the cad drawing if you like.

if you need it in PDF format let me know I'll send it to you that way. I think you'll like the idea. As far as mains go? I'm not sure you can get a big enough spring in those tubes to dampen your landing. I think the infinity gear only travel like 4 to 6" or something like that I'm pretty sure its limited in travel. Motorcycle forks tend to have lots of travel I'm not sure of your background but there is quite alot of math involved in figuring K rates and dampning. I don't want to discourage you. Give it try you may come up with a really cool retract. Remember you don't want to be a pogo stick either. The only thing that I can see that really needs to be worked on, is the inner shock tube is very thin walled steal tubing, that would have to be resolved in order to use them as mains. I think

 

Tony

[airwrench]

Cybersushi

 

I have a really neat idea that I'm implementing on my long Ez using a GSXR 750 fork for a steerable nosegear. I can send you the cad drawing if you like.

if you need it in PDF format let me know I'll send it to you that way. I think you'll like the idea. As far as mains go? I'm not sure you can get a big enough spring in those tubes to dampen your landing. I think the infinity gear only travel like 4 to 6" or something like that I'm pretty sure its limited in travel. Motorcycle forks tend to have lots of travel I'm not sure of your background but there is quite alot of math involved in figuring K rates and dampning. I don't want to discourage you. Give it try you may come up with a really cool retract. Remember you don't want to be a pogo stick either. The only thing that I can see that really needs to be worked on, is the inner shock tube is very thin walled steal tubing, that would have to be resolved in order to use them as mains. I think

 

Tony

Hey!!!!!!!!Love the idea, it is simmering somewhere amongst all the other innovative ideas which I have been hearing lately, could you send me your drawings?? would love to throw them on my cad and do some testing:)

[magnum]

Tony,

I would like to take a look at it also in pdf format when you have the time! Pm me.

Press on

Tom

[tonyslongez]

Magnum, Airwrench

 

Hey guys or gals? I can't see you so I don't want to offend:)

 

I'll try to get those finished this week Ive been going crazy out here in Vegas with T.V. production stuff. I have part of this done in 3D just have to finish the top half. (easier said than done ). Airwrench what Cad are you running? I'll send you my maines too I think you'll like them. Magnum I'll have to do a 3 view drawing for you if you want it in PDF, might take a bit longer but I'll get it to you, Or you can download a Cad viewer on the net for free. Not sure what site is best,but I know it's out there. Jon Matcho is using one he likes that he downloaded maybe we can get him to chime in here. Now just so you guys or gals know I haven't made this nose gear yet though I fully intend on doing so. I want to get my maines done first then I'll do the nose gear. You will have to make some custom parts mainly out of aluminum nothing real exotic and no compound curves, should be pretty easy.

 

Tony

[Jon Matcho]

Jon Matcho is using one he likes that he downloaded maybe we can get him to chime in here.

I downloaded DWG TrueView from AutoCad, which I found much better than the viewer from Bentley. It's free -- you just have to register.

[airwrench]

Magnum, Airwrench

 

Hey guys or gals? I can't see you so I don't want to offend:)

 

I'll try to get those finished this week Ive been going crazy out here in Vegas with T.V. production stuff. I have part of this done in 3D just have to finish the top half. (easier said than done ). Airwrench what Cad are you running? I'll send you my maines too I think you'll like them. Magnum I'll have to do a 3 view drawing for you if you want it in PDF, might take a bit longer but I'll get it to you, Or you can download a Cad viewer on the net for free. Not sure what site is best,but I know it's out there. Jon Matcho is using one he likes that he downloaded maybe we can get him to chime in here. Now just so you guys or gals know I haven't made this nose gear yet though I fully intend on doing so. I want to get my maines done first then I'll do the nose gear. You will have to make some custom parts mainly out of aluminum nothing real exotic and no compound curves, should be pretty easy.

 

Tony

turbo cad, it opens up most everything:thumbsup:

[tonyslongez]

I sent out the 3D drawings of my mains you guys check your e-mails

 

Tony

[athomp58]

Tony,

I would like to take a look at the steerable nose gear adaptation of the motorcycle fork. Please send me a copy of the files. I'm using DesignCAD which can open most any CAD file.

 

BTW can anyone steer me toward the old post that appeared either here or on the Canard Aviation Forum within the past two weeks that had the picture of the canard with the trailing link main gear struts. The original post was a question about identifying the aircraft. It appeared briefly when someone posted a reply. Now, I can't find it. I wrote the contributor to ask if he could post more pictures of the trailing link gear. But, his e-mail link failed.

 

Thanks,

Aubrey

[tonyslongez]

Aubry

 

I worked on those drawings for the nose gear last night. I have to say I wasn't real happy with the way I represented my idea in Cad. So, I'll try again tonight and see if I can get this one to make more sense. Don't get me wrong I know you guys are smart enough to see what I'm seeing:envy: but I want it to be crystal clear to the first time builder. This way I don't have to draw it again:D

 

Tony

[Wayne Hicks]

I suggest you guys take a look at a post via the Cozy search engine.

Go to this link:

http://www.maddyhome.com/cozysrch/message?sn=2&hit=2

 

enter keyword: castorable

from: Zeitlin

 

What you're proposing here -- steerable replacing castorable -- may be a bad thing to do.

[athomp58]

This issue has been debated before (probably several times!) and I mostly agree with Marc on the issue of adding steering capacity. The airframe is not designed for side loads and designing a foolproof linkage to the canard type rudder system may be trickier than it seems. However, I think the Cozy type airframes need an energy absorbing nose gear with a larger wheel. This is partly motivated, for me, because it is looking like I may have to do my initial testing from a 5000' grass field. But, I have also heard several stories about slightly hard landings that could have been disastrous because of the bounce from the springy fiberglass nose wheel support. A couple of weeks ago, while I was at the gym, a show was on TV (without sound) that showed a small jet military trainer with a beautiful, small, maybe easy to copy, trailing link, nose gear. I've been mulling over this issue for several months and seeing the trailing link gear stimulated me to get active on it again.

 

Aubrey

[tonyslongez]

What you're proposing here -- steerable replacing castorable -- may be a bad thing to do.

Well "bad" may be a relative term. I think that having a steerable/castoring nose wheel would be good. We could then avoid the side load issue. that is to say that if your crabbing and forget to put the rudder input in during touchdown at say 10lbs of preasure the nose gear becomes castering. I will be able to adjust that preasure during testing. Think of it as, steering with a shimmy dampner on both sides of the gear leg. If there is to much preasure on the wheel, the dampner simply absorbs your input and the wheel will caster to what ever force is greater upon it. If you press on the peddals at the same time with equal preasure the wheel will remain straight and the dampners will absorb your inputs. Now you are into the braking section of the peddals this way we don't need toe brakes one pedal does everything, it really does work. you'll see in the 3D drawings of it how it's going to work, for me it seemed like the obvious layout for this type aircraft. I certainly welcome everyones input to my ideas. Just be patient with the drawings, not quite done yet,

 

showed a small jet military trainer with a beautiful, small, maybe easy to copy, trailing link, nose gear. I've been mulling over this issue for several months and seeing the trailing link gear stimulated me to get active on it again.

Welcome back Aubry. I'm sure that between all of us on this site we can come up with a good steerable nosegear that won't require to much modification. I think we can do this without a drag link though we'll see.

 

Tony

[airwrench]

Well "bad" may be a relative term. I think that having a steerable/castoring nose wheel would be good. We could then avoid the side load issue. that is to say that if your crabbing and forget to put the rudder input in during touchdown at say 10lbs of preasure the nose gear becomes castering. I will be able to adjust that preasure during testing. Think of it as, steering with a shimmy dampner on both sides of the gear leg. If there is to much preasure on the wheel, the dampner simply absorbs your input and the wheel will caster to what ever force is greater upon it. If you press on the peddals at the same time with equal preasure the wheel will remain straight and the dampners will absorb your inputs. Now you are into the braking section of the peddals this way we don't need toe brakes one pedal does everything, it really does work. you'll see in the 3D drawings of it how it's going to work, for me it seemed like the obvious layout for this type aircraft. I certainly welcome everyones input to my ideas. Just be patient with the drawings, not quite done yet,

 

 

 

Welcome back Aubry. I'm sure that between all of us on this site we can come up with a good steerable nosegear that won't require to much modification. I think we can do this without a drag link though we'll see.

 

Tony

I could see this working, but storage in the fuse might be a little more difficult??.............Hey, what the heck, steering capabilities as small as 30 degrees would be nice..........hydraulicly actuated??hummmmmm.....