Dragonwings on Mini-500

C. Beaty

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Dragonwings on Mini-500

First, I must state categorically that a stock set of gyrocopter blades must not be mounted on a Mini-500. The connection between blade and grip isn’t strong enough.

The Mini-500 has a single 5/8” diameter bolt that carries most of the centrifugal load. To accommodate helicopter loads, a special root doubler had to be incorporated that allowed transfer of centrifugal load between spar and blade grip.

Also, the twist used in the gyro version is detrimental to helicopter hovering efficiency.

As many individuals know, modern helicopters use cambered rotor blades in the interest of efficiency rather than the traditional symmetrical sections first used by the pioneers beginning in the 1940s. That knowledge has been slow in filtering down to amateur helicopter designers.

Gyros can squeak by with rotor blades that have nose down pitching moments and that aren’t balanced about the aerodynamic center. Helicopters can’t. Tail heavy rotor blades, if they don’t flutter, will become divergent at the higher tip speeds used on helicopters.

Knowing all these things, Ernie decided to have a go at DWs on a Mini-500. He built up a set of untwisted blades with reinforced root fittings and with 3.5 lb. brass tip weights.

Subjectively, the performance increase was amazing. A throttle chop and needle split from a low hover results in a slow settling in without touching the collective as a result of reduced rotor drag and increased rotor inertia.

From a low hover, permitting the rotor speed to drop into the yellow can be powered out of simply by rolling on more throttle whereas the original blades will settle in no matter how much power is applied.

Performance was improved in all flight modes; the reduction of rotor power leaves more power available for maneuvering and no doubt would improve engine durability and reliability.

Many of the fatal accidents with Mini-500s have been the result of engine failure combined with marginal autorotational performance. Low drag, high inertia rotors would mitigate those risks.

Quantitative measurements require more instrumentation than is incorporated on a Mini-500.

With 4-stroke engines, manifold pressure is a good relative power indication but is not applicable when using a Rotax 582.

A main rotor shaft torque meter would have been nice, as would have been a sensitive fuel flow meter.

I have a number of photos but the attachment link doesn't work.
 
Chuck,

If you can't get you attachments to upload, email them to me and I can edit your post to attach them.

Oh yeah, does your neighbors computer have a 'pop-up' killer installed on their computer? That would prevent the attachment screen from...well, popping up! If so, maybe it can be disabled while you upload.
 
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Subjectivity...

Subjectivity...

Maybe the performance increase Ernie experienced came from translational lift provided by all those 150 mph winds from the hurricanes blowing through Florida?
 
Thanks, Mike. It was my own fault; -I had just installed Netscape 7.2 which incorporates a popup blocker and I wasn't smart enough to figure it out on my own.

Hopefully, here are a few of the photos of the Mini-500 flying with DW blades.
 

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Any Updates on hows these worked out, was just looking up old posts about the Mini-500 after watching one of my old Mini 500 videos. I did read alot of reports of the Engines seizeing in these helicopters.
would be intrested to hear what became of these tests and where they ever marketed to other Mini 500 owners.

always liked the looks of the Mini 500. but the rep kind of scares me.
I know of a nice one for sale right now at a great price,but after reading all the engine problems I have second thoughts of even looking at it.
was thinking about getting it play with and resell later on.
 
Ernie had no intention of keeping the Mini-500 or of flying it any higher than he was prepared to fall. He just wanted one to play with for a short time.

He sold it along with its original banana shaped blades shortly after those pictures were snapped. He kept his own modified blades, not wanting it to bore a smoking hole while flying with his blades.

DWs are the standard blades on the Mosquito but that’s different story.
 
was just wondering,since from what I read in the post it really improved the proformance, was wondering if it could have been the key to not siezeing the engines. seems alot of these helicopters crashed from sudden stopage.

But I don't know much about them. seems to still be several around flying. but even more for sale. I read on one web site a kit was $32,000 when they where new.

and I have seen many listed for under $18,000 now complete.

besides the turbine conversions I wonder if anyone has tryed any other type of engine in one.

I know of one here in n.c. for sale at a good price and it got me reseaching it. lot of intresting reading some good.alot not so good.

Alot of crashes where pilot error. I was discussing it with my Business partner who is a helicopter CFI. and he brought up another good point.

got to wonder how many of these the people really new how to do the tracking and balanceing on.

I mean even on here we read of people working on getting the blades smooth on a gyro, A helicopter is 3 times worse to get adjusted.

I know when I played with my Hobbycopter it took me weeks and weeks of adjusting before I got them smooth. never did get them smooth on my scorpion.

To bad they dragon wings where never offered to the public for the Mini's if they autoed better, who knows could have saved a few lives.

just some thought to ponder.
 
Sorry gentlemen, but somebody could tell my which torque is needed for both nuts to attach blades to rotor head on my Mini500?
Thank you for your help
J.-C. Schlup
 
Very interesting Chuck…..I guess I'm surprised the DW's were so much more efficient than the original blades….unless these original blades aren't 0012 airfoils.

I take it that the original Mini-500 blades do not use the NACA 0012 airfoil?

Do these untwisted DW blades have the same airfoil as their gyro blades?

Thank you Chuck…..
 
Yes. Same airfoil as standard DWs but without the twist.

I don’t know the details but I expect the Mosquito blades have appropriately designed root fittings. The blades used by John Snider in the Utube video performing hovering autorotations from 20 feet had extra tip weights.
 
Chuck,

Little confused by your post...

Are you saying DW's are a bad idea for the MH-1?

Or are you saying that stock DW's are a bad idea, but the one's Ernie fitted with beefed up blade grips, tip weights, and not twist are suitable (and/or preferable) to the stock Mini-500 blades?

From my experience (1000+ hours in a UH-1, 1500+ hours UH-60) the high inertia rotor blades of the UH-1 were preferable to the low inertia blades of the UH-60for autorotation. UH-1 auto was EASY, and smooth. In a UH-60, you drop at 3400 fpm... End result: UH-1 much more forgiving to incorrect attitudes and flare heights from students.

Obviously, the low inertia systems have great advantages in performance and speed and maneuverability, and with the second engine on the UH-60, the chances of autorotation were greatly diminished...

That having been said, I can see no reason why higher inertia blades on an experimental helicopter would not be a GOOD thing. I certainly would opt for higher inertia blades.

I am wondering if the "cruiser" blades Ernie has for the DW's that Russ just did a pilot report on are the same blades? Hmmmm.
 
... The blades used by John Snider in the Utube video performing hovering autorotations from 20 feet had extra tip weights.

I am familiar with the video you mentioned and I have to ask, from the way you've put it, those "...extra tip weights" on Snider's XE, are they standard or at least an option now with the blades normally supplied with the Air or XE kits?

tyc
 
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Spencer, Ernie didn’t want to sell rotors for the Mini-500 for a couple of reasons:

First: the likelihood of splattering for unrelated cause was too great and would have sullied the reputation of DWs. Not worth it considering market potential.

Second: as an orphan, no one had oversight responsibility.

In the case of the Mosquito, John Uptigrove is a qualified engineer and approves root fittings, tip weights, etc.

***************
Tyc: I’m not sure. I know the first set of blades with more than usual tip weight was custom made for John Snider but I think I heard mention of John Uptigrove standardizing on the heavier weights. It’s his call.
 
Tyc: I’m not sure. I know the first set of blades with more than usual tip weight was custom made for John Snider but I think I heard mention of John Uptigrove standardizing on the heavier weights. It’s his call.

By coincidence, just the other day I came across two JPGs of a yellow XE, advertising "Dragon Wings" on it's side ... You Tube I think.

tyc
 
Interesting. I have no idea who it might be.

Ernie flew one for a couple of months but sold it. That’s was ~ 2 years ago.
 
By coincidence, just the other day I came across two JPGs of a yellow XE, advertising "Dragon Wings" on it's side ... You Tube I think.

tyc

It used to belong to Dad but, he sold it to John Schnider. I am not sure what he did with it.
 
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