RAF HS choices

[Doug Riley]

I'm trying to take Chuck Beaty's sound advice, and contribute some articles to Rotorcraft mag. One will be about H-stabs.

What are the current sources of H-stabs for the standard RAF, besides the full Sparrowhawk conversion? The last time I looked, the three that I recalled(Ken J, Bad Stab and Parham) were out of business. Are there others still around? Has any sucessor bought one of these guys' molds and started up again?

How about the Brits and Aussies? Any blokes selling them in those countries?

Thanks.

[GyroRon]

Aircommand International makes a replica of the Parham stab. It will work on any gyro, not just aircommands and RAFs

[paulp]

If memory serves, someone posted on the forum that they had the old bad stab molds that they got from Larry Martin. I personally would like to know if I could borrow the pluggs and mfg my own stab. Having had some experience with fiberglass as well as carbon fiber I could probably make two and possibly trade one for the use of the molds.

[PW_Plack]

Not likely the Brits will be doing it...it's illegal there to add a horizontal stab to an RAF.

[Friendly]

paulp . The molds you spoke of are here in Louisiana and they are free for any one to use . I just wanted to make sure that the stabs were replacable. If you are interested my cell phone is 318 308 2400

[KenSandyEggo]

Alan will ship one from New Zealand for $999 including freight.

"Hi Ken,
Please advise anyone interested in my stab that the price is US$999 delivered to their door. I will try and keep one or two in stock - so that delivery in 7 days is possible."

aloughrey@xtra.co.nz for details. I will vouch for Alan's honesty. Paul B. should be able to pipe in with more info.

I tossed my molds into the Miramar landfill. Wasn't worth it anymore. What's funny is when I came out with my stab, Larry as much as called me a thief, claiming I was ripping people off. He decided to market his own and sell them at a much lower price. Just before he folded up, he had raised his price to exactly what I had been selling mine for.

[Alan_Loughrey]

Ken - Thanks for your intro and kind words.

Doug - I am presently making to order stab design #6 for the RAF 2000.
It took me a while to realise a gyroplane needs the gyro equivalent of a Static Margin for it exhibit stable flight characteristics. I.e. The stab has to cancel out the nose-down pitching moments produced by the offset prop thrust, cabin shape and undercarriage drag before it can also support a “Static Margin”. With this goal in mind I have moved to highly cambered foils with end plates and the results are pleasing. At 60mph the stab moments exceed prop thrust moments making a PPO a highly unlikely event. A most interesting bonus is the 10mph higher cruise speed achieved with the same engine RPM. I presume this is due to a reduction of the rotor's induced drag.

The photo shows testing #6. Area = 6.3sq/ft, CL = 1.55, Foil NACA 0010 with fixed flap. It is mounted on a tube, the AOA is ground adjustable.

[IMG]

[Doug Riley]

Alan: I agree with your analysis. The HS should, as installed, completely overcome the nose-down moments from prop and body in all steady flight regimes (including slow full-throttle climbouts) and still have reserve power.

Do you offer these units for sale and, if so, could you post your contact information? I'm gathering info for an article (which incidentally will not evaluate the products, just list the sources).

Thanks.

[Alan_Loughrey]

Doug - I manufacture stabilisers and rudders and other sundry fibreglass items.

I agree with your comment “(including slow full-throttle climbouts)”. Perhaps that can be accomplished with a powerful stab with in-flight adjustable AOA to reduce pitch-up tendencies at higher speeds.

My contact details are -
Email : aloughrey@xtra.co.nz
Phone : Country code 3 489 8222

1 Precelly St
Allanton
RD2 Mosgiel
Otago 9032
New Zealand

[Doug Riley]

Alan: Thanks for the info. It seems to me that a stab partially immersed in the prop wash and having negative incidence and/or negative camber is the right solution IF the gyro has nose-over moments caused by the prop or frame drag. The immersion makes the HS's power adjust itself automatically to the throttle setting, which is to say to the amount of nose-down moment from that source.

Have you actually encountered unpleasant pitch-up tendencies at high speeds that are NOT attributable to the onset of retreating-blade stall? In a gyro, this stall comes on gradually and acts as an automatic speed limiter. If the HS starts to create an objectionable amount of nose-up trim change at speeds BELOW the onset of blade stall, then, yes, something would have to be done with adjustable incidence or otherwise.

[Alan_Loughrey]

Doug - A stab immersed in the prop wash look to be the ideal solution. In a practical sense it is a little tricky to attach to the existing RAF rudder. But I am working on a rudder for another machine and may swap it across to a RAF for a short period to measure the effects.

With highly cambered stabs the RAF runs out of pitch trim at higher speeds and your arms get tired holding the stick forward. (Best - I think - to rake the mast to its fullest extent.) My one and only experience was of a very stable ride in the region of 90+mph IAS, not unpleasant in the least. Stab trim would have been nice, but my friend doesn’t cruise at these speeds and deemed it unnecessary. Pic of stab below.
[IMG]

[Aussie_Paul]

I am away from home for a few more days. I up the top end of Oz approx 122 miles east of darwin. I have been setting up a new Raf with one of Alans stabs, the same as I flew down at Perth prior to Christmas. I will post some pics and info when I return homr in the next couple of days.

O.B. Aussie Paul. :)

[Brent_Brown]

I said this before. the existing RAF fin part of the rudder can be made longer front to back and that will give you room the put the HS on top of the fin and you can still use the same cables and all. I would do it if I had one. A big fat T tail right up to the prop and about 18" cord.

[Brent_Brown]

An idea of what it would look like

[KenSandyEggo]

If I recall correctly, we had looked at putting the stab at the top of the RAF rudder, but the structure was too....I don't want to use the word flimsy, because it wasn't designed to hold a stab....but the structure wasn't strong enough to attach anything the size of a decent stab to it. In most cases, I believe a horizontal and vertical spar are needed for support. Don't think there was any kind of spar in the RAF vertical tail.

[Brent_Brown]

That is why I would add it into the longer fin and HS. as it is the fin would not hold the HS.

[GyroRon]

An idea of what it would look like

That is just plain ugly Brent. You know it... I know it... we all know it. We all also know that people who buy RAF's don't buy based on safet yof handling, they buy based on LOOKS!!! so you would end up the only one with a ugly stab! :D

Must be why Larry Martin got out of gyros. To make them right, they end up ugly. He told me once that looks mean everything, or something to that effect....

[Brent_Brown]

Ron that is about it. I give up.

[GyroRon]

I was making a smarty pants comment Brent. That one where people tell me that try would rather have a Sexy RAF with it's sleek lines than a tall ugly gyro like the Sparrowhawk.

I have had several RAF owners tell me they don't have a stab on their machines cause stabs are ugly.

I have also had several RAF owners tell me they had no stab cause they didn't want to bang their shins on one while walking around the gyro.

So please don't give up, I was just making fun of the ignorant people out there that place value on looks over true safety.

[Harry_S.]

Ron:

You have a lot of gall calling people ignorant!!!


.

[GyroRon]

Harry don't you have a stab? that would take you out of the ignorant category and place you into the smart thinking man category!

I understand that a few years ago there was no Sparrowhawk to cross shop RAF with. So you bought a RAf because that was your only choice.

Then you read about Stabs on the web and in magazines. And see Stabs on RAFs at the fly ins and talk to the owners.

THEN.... the big decision factor comes in. Add a stab or not. If you decide not to add one cause it is ugly or cause you might bump your shins into it..... Well I say that is ignorant. How else could you see it?

The gyro has a thrust offset and a powerful engine. There is no way to get around the fact that the gyro is a dangerous machine without at least a stab. It can easily kill you. A stab is a HUGE safety improvement for the RAF. It is such a improvment that only one RAF with a stab has ever gone down, compared to what 10+ RAFS without? To me this is a improvement that is a absolute must have. To continue to fly without one cause it looks Ugly or cause you might walk into it is ignorant as best.

[GyroRon]

and to be fair to Harry, the same thing applys to those with low rider aircommands that refuse to add a stab or the CLT retro kit cause they think the stab is ugly or they think a tall gyro is ugly.

Same thing applys to anyone who dismisses advancements in gyroplane design cause of the way it looks.

Go sell your gyro and get into classic cars or boats. Something where you can base your purchase on looks and can still be safe. Function should follow form in aviation, or at least when safety is at stake. Why not?

[StanFoster]

Harry: My annual is done...I am loaded for an ultralight gyro exhibition in Springfield tomorrow.

To keep with the topic here....you can see my stab on my RAF. :D

I cant wait to get back into the air with this machine...and start another year of flying.

Everyone have a safe and fun year of flying...and lets all try to respect others and the type of machine they choose to fly. We are all trying to fly safe...

Stan

[Jerseywing]

C'mon Ron, if it ain't pretty then how can you win friends and impress people with your toys. :rolleyes:

Lets face it, Orville and Wilbur's contraption was a dog but it flew (sorta)

[Harry_S.]

Stan:

Sure looks purty to me. :D

Where do these people get off by calling that machine *ugly* :confused:

Stan...you didn't trailer that beauty stickin' out bare like that?! I would have a sheet of armor plate out in front of her. ;) [Maybe have her back to the wind, too] :)


Cheers :)

[Harry_S.]

I'm trying to take Chuck Beaty's sound advice, and contribute some articles to Rotorcraft mag. One will be about H-stabs.

What are the current sources of H-stabs for the standard RAF, besides the full Sparrowhawk conversion? The last time I looked, the three that I recalled(Ken J, Bad Stab and Parham) were out of business. Are there others still around? Has any sucessor bought one of these guys' molds and started up again?

How about the Brits and Aussies? Any blokes selling them in those countries?

Thanks.




Sorry Doug...I think we hi-jacked your thread.


.

[Aussie_Paul]

The Raf fin has a 3/4" diameter chromoly tube as a vertical spar.

Aussie Paul. :)

[birdy]

Where in the fin is it Paul,?? I need something solid to brace me stab to.

[GyroRon]

Stan:

Sure looks purty to me. :D

Where do these people get off by calling that machine *ugly* :confused:

Stan...you didn't trailer that beauty stickin' out bare like that?! I would have a sheet of armor plate out in front of her. ;) [Maybe have her back to the wind, too] :)


Cheers :)

Stans Machine would be the Sexiest gyro out there.... except for that Damn whale tail thingy on the back that people keep tripping over! :D

[StanFoster]

Ron: Yea...I have a bruised shin from pushing that into the show yesterday. I am taking my stab off. :eek:

For sale....one Parham stab....

it may cause ground handling bruises...

on the other hand...it helps prevent a buntover


Not For sale....my Parham stab :D



Stan

[Jerseywing]

You could always try shin guards :confused:

[Brian Jackson]

You could always try shin guards :confused:
I'm thinking more "guard rails" :D Outside of the parasitic drag, these could be real shin-savers! Besides, you can paint them whatever color you want... (model shown in natural finish)

[Jerseywing]

LMAO thats a great idea!!!!
(but you may have to do a new weight and balance)

[StanFoster]

Brian: Good one........now I have to move my mast to change my cg.

Stan

[birdy]

I'v never had a shin tap'n problem with me hinged stab Stan. :D

[Aussie_Paul]

Birdy, I will find the broken bit and measure for you. Could you please send your pvt email to me at mail@firebirdgyros.com

Aussie Paul. :)

[birdy]

Wots that???
If you mean the email adress thingy, you'll av to wait till the MF gits back from town, coz I don't know wot to do.

[Michael J. Ston]

Folks...
Anyone looking for one of Ken's stabs? I have one that I will sell due to the fact that I have went the AAI route. Ken's stab has never been flown. The stab had only been partial mounted to the keel and never painted (still in primer gray). If fact, I would be willing to throw in the original RAF vert stab and rudder just to get my shop area cleaned up.
...Mike (Houston Area)

[tomhall]

I am looking for anyone who has mounted Don Parham's HS directly on the RAF keel. I have extended my keel with Don's 18" extension, 2 plates and lots of rivets. Some suggest the HS be perpendicular to the keel, others say it should be perpendicular to the actual prop thrust ?! After building for 2 1/2 years I am almost done and will be with Ron Menzie the week of April 18th !

[Harry_S.]

Stan's your man, Tom.


Cheers :)

[Udi]

I am looking for anyone who has mounted Don Parham's HS directly on the RAF keel. I have extended my keel with Don's 18" extension, 2 plates and lots of rivets. Some suggest the HS be perpendicular to the keel, others say it should be perpendicular to the actual prop thrust ?! After building for 2 1/2 years I am almost done and will be with Ron Menzie the week of April 18th !
Tom - take your new RAF and the stab to Ron Menzie and install it with him. Ron knows what he is doing! If you can have Ron test fly your gyro, you are set.

Udi-
p.s. I say install the stab with a negative 2-3 degs to prop blast.

[tomhall]

As always, my best advice comes from y'all ! Thanks. If anyone wants to see the extended keel, go to : www.eaa100.org and click on Projects. T. Hall

[LAWOLF]

Please send me a RAF gyro picture so I may look at it to understand the design. Send picture to dlaw@hlaircraft.com.

[barnstorm2]

Please send me a RAF gyro picture so I may look at it to understand the design. Send picture to dlaw@hlaircraft.com.

Here are some from last years Bensen Days.

One stab(le) one not.

[Harry_S.]

Udi:

Are you insinuating that no one else, other than Ron M., knows anything about installing and evaluating the Parham stab,,,to the keel of the RAF???

That's way out in left field.

Stan F. installed the Parham stab...has flown it for over a year now and is quite happy with it. I believe Stan is well qualified to comment on the Parham stab.

Not to belittle Ron M., but Ron himself flew the RAF stabless for quite a while before a student brought his stabbed RAF for instruction and... after Ron flew his student's RAF, Ron was impressed at how stable the stabbed RAF handled. Check his website.

Pat M. in Florida has the Parham stab with the extension. Pat, I understand is very happy with that installation. Maybe at Bensen Days, Stan and Pat can get together and compare notes?!


Cheers :)

[Udi]

Udi:

Are you insinuating that no one else, other than Ron M., knows anything about installing and evaluating the Parham stab,,,to the keel of the RAF???

That's way out in left field.
I was not insinuating anything, Harry! Tom is visiting Ron Menzie in two weeks anyways, so I suggested that he takes advantage of Ron's experience to set up his stab. How did you get the idea I was insinuating anything??? Ron Menzie has flown the RAF with no stab, with a few kinds of stabs and with the AAI kit. I think he has tinkered enough with his RAF as to gain my respect! Ron knows what he is doing. I said no more and no less.

Udi

[rgraffeo]

Tom,
I mounted my Parham stab under the keel.

[StanFoster]

Tom: Here is a picture of my Parham stab on my RAF.

It flies beautifully!!!. I have over 170 hours with it. It is set 2 degrees nosedown with the keel.

I have measured the in flight keel angle at 55...65..75...and 85. The keel measured flying with a nosedown angle of 2 degrees.


This means my stab is running 4 degrees nosedown with the relative air flow.

The nose does NOT go lower with higher airspeeds. Now that I have Sportcopter blades on my RAF and have attained speeds of 100 plus....the nose is still right there with no detectable nose down tendency.

You can see where I beveled the little aluminum spacer spools to fit the airfoil . There are some shim washers on my attachment bolts to adjust the pitch should I desire to.

I am not touching it....it pleases me every flight. :)

Stan

[Harry_S.]

Ok Udi.

I thought Tom was wanting info regarding the Parham stab...now. That's why I tried to refer him to Stan F. I knew Stan installed the Parham stab directly to the keel, before he even test flew his RAF.

I knew Stan is quite happy with the stab...quite happy with the whole machine, actually. He had sent me a beautiful close-up pic of his stab and I was hoping he would post it for Tom; and he did. ;)


Cheers :)

[dragonflyerthom]

This was the discussion of the Horizontal Stabs in 04. Looks like it showed some promise. Keep up the good work Doug R.

[Doug Riley]

Thom, Alan Loughry has, I think, done more real, numerical testing with gyro H-stabs than anyone else. Among other things, he claims to have gotten much higher lift coefficients (more lift per sq. ft. at a given speed) from H-stabs than I have, by using end plates. The tests I did were without them.

I wouldn't bet the farm on this, but it's an area for further investigation and wind-tunnel-type testing. Note I didn't say test-flying. It's foolish just to slap something that "looks pretty good" on your gyro and go fly. "Flying" your H-stab on a test boom on a car is quicker, cheaper and safer.

Another area that's ripe for investigation is mapping the propwash. Until you know what airspeed you find where, you can't design a H-stab that is anything more than an uneducated guess.

Given the crashes we've had with H-stab equipped gyros (other brands as well as RAF's), we should be designing in a way that makes success more likely. That means doing some homework, not cut-n-try experimentation.

[dragonflyerthom]

Doug

You are right about everything. One and probably the major problem with it all is the small number of gyros and gyro pilots. Since we are such a small part of general aviation we get lost in the shuffle. Hopefully that is about to change. If one could get everything done by professionals it would be done in the scientific method with blind studies. It would also be nice if some of the larger companies would make their research available to us.

[Hognose]

Doug and all --

Tom Monard had one of Alan's stabs (no idea which iteration) on the Peasant Frog. I may have detail photos of it ratholed somewhere.

cheers

-=K=-

[Aussie_Paul]

This is the prototype of what Tom had on Peasant frog. Allan was trying to get approved in the UK. We gave up and went back to Firebird.

Aussie Paul. :)

Storch and G-200 on lake bed that had not been dry for approx. 100 years
UK stab 1 wps.
UK stab 2 wps.
UK stab 3 wps.

[dragonflyerthom]

Doug

One of the things I am trying to do is to find out who is making H/S stabs these days. I can only think of two at present. I am hopeing Steve O and Larry B will be getting theirs done soon. Larry says it really does make a difference in the static stability of a RAF. I presently have the LM bad stab on mine and it does the job but I want the best for my bird.

[Aussie_Paul]

Doug
but I want the best for my bird.

Thom, if that is so conduct the stepped keel mods, as the h/stab is nowhere near as important after the stepped keel mod has been conducted.:lol: :lol:

Aussie Paul. :)

[dragonflyerthom]

PB

You are right. I have all of the material to do the steeped keel mod. Cluster plate material and 3/16 rivits. Just waiting until the 40 hours have been completed then I can do it. At present I am in the middle of tax season. Working 12 hours a day. April 17 will be the end of it this year then I can do what I enjoy in my off time.

[JR_T]

Tom Monard had one of Alan's stabs (no idea which iteration) on the Peasant Frog.



Here's a couple photos of Peasant Frog taken at BD last year.

[Doug Riley]

Going by memory, Alan reported maximum lift coefficients (C.L.) of somewhere around 1.4 with tip plates. The chart I've put up here previously goes up to only C.L. = 0.8, as I couldn't get anything higher than that with my tests of a no-plate stab.

Lift per square foot of stab area at 60 mph is about 9.2 lb. x C.L. That's 7.4 lb./sq. ft. for my simple HS (C.L.=0.8) and 12.88 lb. for a C.L. of 1.4.

Even if 1.4 is correct, it's achieved only at 12-14 degrees AOA and requires over 6.5 sq. ft. of area to just BARELY save your bacon. This assumes a PPO moment of 600 ft.-lb., which is reasonable for a stock RAF.

If a smallish stab is mounted with little or no incidence, then it can't stop the PPO until the machine has pitched over some 12 degrees. At that point, the gyro's body has built up some rotational momentum, which requires EXTRA HS force to stop it. That extra required "braking" force can be enough to stall the HS if it's marginal to start with. Over you go, stab and all.

Low-mounted stabs are somewhat less effective thatn higher-mounted ones, even if you don't consider propwash effects. The thrust of a stab is directed down-and-back (there's a "back" component, just like there is with rotor thrust). The "back" component (=drag) is useless and even counter-productive. A centered (or above-center) H-stab has a better leverage position.

Reducing the PPO moment by moving thrustline toward CG is pretty much a necessity if you want a complete and reliable RAF fix. You can probably do it with stab alone, but the stab ought to be about four times the size of the Peasant Frog's. Anything less is a partial fix.

[reelmule]

Alan: I agree with your analysis. The HS should, as installed, completely overcome the nose-down moments from prop and body in all steady flight regimes (including slow full-throttle climbouts) and still have reserve power.

Do you offer these units for sale and, if so, could you post your contact information? I'm gathering info for an article (which incidentally will not evaluate the products, just list the sources).

Thanks.
Doug, I can vouch for Alans honesty and quality of his current 6th gen HS. I have flown this stab over 120 hrs solo and duel. I fly the 2.5 RAF with the
RAF stabilator which I thinks gives the best of both worlds-rotar stability and frame stability. I fly this at -2* incidence; at IAS of 90+mph forward stick is necessary but no signs of onset of RBS. Plan to install co-located pitot and static pickups so will have accurate ASI.
Walt G.

[reelmule]

Doug and all --

Tom Monard had one of Alan's stabs (no idea which iteration) on the Peasant Frog. I may have detail photos of it ratholed somewhere.

cheers

-=K=-
Kevin, Tom Monards HS was the previous generation and considerably smaller overall. One nice side benefit of the endplates is the enhanced yaw stability with the doors on.
Walt

[dragonflyerthom]

Doug R

Your insight and research is like mastercard priceless. Thanks for all you have done so far. I look forward to your new research. What you have done and are doing for safety is such a resource for all of us that I really can't say how much we appreciate it.

[Skyjinks]

Not likely the Brits will be doing it...it's illegal there to add a horizontal stab to an RAF.
__________________
Paul W. Plack

Not quite Correct Paul. There has been one designed to meet 'Section T' by Ronnie Legg and it is as far as I am aware awaiting a CAA test having gone through PFA approval.
Skyjinks