Shawn,

By flat rated do you mean at the turbs mid power band range, and would that coincide with the max input acceptance of the MR G/box of the Hybrid?
PeterR-B

Maybe not so daft. Enstrom did this 15 years ago to an F28 and came up with the TH28 which became the 480. It would make more sense to do it with a R44 though.

The engine is mounted where the tailboom normally goes... Would the tailboom be fitted where the piston engine used to be?

They probably wanted to use the exaust gases to do some kind of hot NOTAR System. Now that would be something new.
Somebody asked about the tailboom. He does not have it.
Could it be possible, that he forgot it?

Shawn

Why that? What is the problem with those clutches?

Shawn,
'Vertical C G, Lateral directional stability, negative dihedral, main rotor- CG relationship, C G movin up, governing the turbine'........damn! You been readin' some serious books!
Ah,....BTW ........neither the Allison or the R22 had a centrifugal clutch last time I looked.
Maybe you test-piloted a different model.........

I doubt you could call this thing a derivative of the R-22.

On e-bay it seems that one would have to do most of the mast, swashplate, rotor, tail to finish that project.

Just because he hangs a runout R-22 cabin section on it, it does not mean it is a turbine R-22.

I would call it a derivative, if he puts a turbine in it with a reduction gear to match the speeds and keeps everything else R-22.

A turbine does NOT make any sense for the R-44 as the price would go way up. A new Lycoming 540 for the Raven II is around 48.000,- $
The smallest Turbine, probably some RR 250 model at least around 280.000,-

Besides that the R-44 would not use all the power, the fuel consumption would further reduce endurance, and the price goes up to around 590.000,-. Too close to the Jet-Ranger and MD 500.


3top

The funny thing is that someone seems to have to placed a bid on it! :p

I agree with 3top on this... it's an experimental project that happens to use the cabin of an R22. A conversion project, it is NOT. I'm not sure where all the negativity is coming from. If we never explored or did anything different, where would aviation be today? Isn't that why the X-Prize exist for the next frontier?

For those of you who've been on this forum for a while, you've seen my posts on the "experimental" helicopter topic. Although I choose not to make the attempt personally (time, finances, and lack of mechanical / engineering skills), I admire those who have that kind of passion and ability.

Heck, I'd love to hang a 200-hp turbine off the back of a 300CB, just to have a turbine-powered 300CB!

Oh yeah, I guess that's the 333.

Anyway, the choice of the R22 for this project seems to be driven by the same reason R22s are used almost everywhere - it what they could afford.

Heck, forget R-anything, just consider the rotor system. The teetering rotor offers precious few advantages from an aerodynamic & safety standpoint, yet they are everywhere because they are cheap to buy and operate.

Now how cool would it be to plunk the rotor system from a 300CB on top of that turbine R22? :}

(BTW - I am aware of the two-blade advantages in certain work, but there are lots of Bells and Robinsons out there doing everything but those jobs.)

I am actually surprised that there are not more bids yet.
If the C-18 is in good condition it alone is worth it, though they are not supported by Allison/Rolls Royce anymore.

For those who doubt the project go and look at
http://helicycle.com/

This "R22" would be a logic extension of the Helicycle.

For a more "advanced" concept go to
http://www.rinke-aerospace.com/

Although their product is no more available to the public:

They planned a 2-seater with a 250-turbine, up to 5 blades, etc.
Also a good story about a Turbine-Mini-500 there.
I too admire Experimenters who dare to do Rotorcraft (although I don't care for cheap nonsense..). Just in this case it is no good to call it a "Turbine-R22".

3top
:cool:

I just visited with Stuart Fields who is starting a magazine called Experimental Helicopters.
Stuart and his wife were associated with the gyrocopter magazine for quite a few years.
I visited his house and saw the work :mad::mad:'d done on his Safari (aka Baby Belle), and it was quite good both construction and modifications.
If you're into helicopter experimentation, this is the place to start looking. Issue 1 of the magazine was quite good.

If, and I really mean If you took a similar Turb that did have OEM back up, the R44 would be the ship to try it in, for there looks like plenty o room where the 6 potter would be taken from plus the G/Box would be strong enough? and the fuel tank big enough so all in all, why Not?

Vfr

Shawn, please post the contact information, website, or magazine subscription info.

C20 turbine h300
 

A C20 was fitted into a standard h300 about 12-15 years ago and flew OK.
I will search for photo

I'll post it as a separate thread.

R22 AD Issued 22 Sep 04
 

Interesting...

http://www.airweb.faa.gov/Regulat....909.pdf

hey Rickster, the link don't work. I'm fairly interested in the contents of that file.

This one works


http://www.airweb.faa.gov/Regulatory...8?OpenDocument

Turbine R22
 

Just found this on ebay.com 5924073142.A Robinson R22 with a jet engine,as if it isnt scary enough with a piston.Must have been on steroids.

Done or at least it looks like the same ship.

PW

manifold pressure in R22
 

Hovering IGE a beta 2 with me (160 lbs)and little fuel (about 5 US gals) noticed a rather high MAP (23 ish) -refuelled to about 26 US gals and hovering MAP was about 21. Does this make any sense(change of C of G ???) or is the gauge (or pilot) a bit suspect?

carb ice perhaps?

hands_on123,

Please could you explain how having carb heat applied increases demand for power? Thanks.

Its late and I m jet-lagged so may be talking b'loks but won't carb heat reduce the power available due to the difference in air density compared with unheated outside air?

PW

I think what hands_on123 is meaning, is that if you are in a hover for instance, and you apply carb heat, there is a reduction in power, and helo will sink, but if you apply more power to hold height, you will be hovering at a higher power setting to maintain hover height. Please correct me if im wrong, im tired and grumpy, having had 3 weeks of !!!!! weather I havnt flown much.
Also, cholmondeley maybe at the first flight there was not much wind, and then maybe the wind picked up so you benefited from translational lift, so you got an increase in lift for no increase in power, causing helo to climb, so you needed to reduce the power setting to hold height.
Preparing to duck. :D
Hughesy

I think the overall effect of carb heat in the hover is to reduce MAP for a given throttle position. I don't see how it changes the power "demand". The power required is surely exactly the same.

I agree that the wind effect (or recirculation effect) is probably the most likely answer to the original question.

almost there
 

well, yes, carb heat reduces power developed--for a given throttle/collective position.

But it's not that you then have to pull more power, for the airframe itself doesn't see the carb heat, it just needs the same amount of power to beat the air into submission as it did in the first place.

So you have to increase the THROTTLE ("pull power") in order to open it farther and let more, but thinner, heated, combustion air into the engine, in order to produce the SAME power as pre-carb heat.

Throttle open farther will reduce suction in intake manifold, so the MP will show a higher number. Lots higher, most of us "discover" we forgot the carb heat was on when we flinch at the outrageously red-lined MP.

Now, ONWARD! To the methodologies of splitting hairs with only an Exacto knife and a hand lens . . .

Why would anyone want to apply carb heat in the hover ? You only need carb heat below 18".
That's why people get a rough engine during warm up - carb icing occurs even before they think of applying some power for a lift. Happens all the time - student sits on the ground doing slow checks, goes to lift - rough engine.

Robinson Safety Notice 25 says

So "keep out of yellow arc" (and current advice appears to be a more conservative "keep between 10-15 DegC"), unless below 18 inches MAP in which case ignore DegC and apply full carb heat.

RC

104% of what?
 

Hi there - I suppose I should know the answer but I don't. Can anyone give me a simple explanation...

I fly the R22 - normal operating ERPM and RRPM is top of the green at 104% - ok, fair enough, but 104% of what? Where does this come from?

Thanks, in anticipation of any replies.

A very simplistic explanation is "100% of the design RPM".

Most likely, the original A model ran at 100%, and with time and experience, it was found that 104% gave better results with an acceptable increase in wear and tear.

In the S76B, we run at 107% - you may ask why the gauge doesn't get recalibrated to read 100%? Forked if I know, maybe too expensive to have different gauges for different machines.

I have always considered that RRPM in percent is easier to cope with than the raw numbers.

the figures are percentages of 2550rpm (engine) and 510rpm (rotors).

2550rpm is actually 100% rpm. the engine is derated to 131bhp (O-360) at 2652rpm, which is 104% of 2550 :)

hope this helps.

Jim

Carb heat = reduced air density = less oxygen per mass of air = less fuel burned per mass of fuel = less HP.

Less HP = govornor opens throttle butterfly to maintain RRPM = higher MP for same blade pitch (same HPR).

However, in this case higher MP does not = more HP so manifold pressure limits do not apply, as MP limits are designed to keep max continuous engine output <= 124 hp (or <= 131 HP 5-minute takeoff).

Super simple, huh.

While we are on this subject, I know that hovering downwind needs more power ie higher MAP. But why? I ought to know this and probably did once, but I even consulted Shawn's book this week and could not find the answer there either.

Why does the rotor disk care which way the wind is entering it? Because the TR is in the way of the airflow?

Muffin: because hovering downwind is actually flying backwards. 10 kt wind from behind = 10 kt flying backwards to maintain your position relative to the ground. And flying backwards isn't the most aerodynamic thing....

To the rotor disc, it does not matter whether it is 10kts from in front/side/rear - However, like it or not, hovering downwind your feet will be working like mad to keep you straight and wasting all that excess power.

TeeS

I heard that re-certification of the gauges to show 100% was too costly.

Besides, if the needles are in the green they're fine, so we can spend more time worring about the carb heat / MP comparison, where the wind is . . .

Well, at least you realised that there was a question! A little while before my FI test, I asked a couple of f/w PPL friends if I could practise doing a briefing on them. It was all going well, until one asked, just as you did: "104% of what?" It stopped me in my tracks at the time, as I just couldn't think of an answer that made sense and was easy to understand.

"large translational lift effect that occurs at that speed?"

When you wake up and smell the salts, you might want to consider whether there IS a large translational lift at 10 kts.......and you could also dig out the original R22 and R22 Beta POH and take a look at the section on carb heat.

I'm only pedantic when I'm sober, but perhaps you could explain why you think an R22 going backwards at any speed is better than or equal to the aerodynamic efficiency of one going forwards ?

If you can, then copyright your answer immediately before an engineer makes use of this new law.

(And to the original poster who no doubt just wanted a simple answer........welcome to pprune.) :}

When we think "hovering downwind", what we are really doing is hovering in a reduced/zero airspeed state (compared to hovering upwind).

Less airspeed means higher AOA for the same lift, so more drag, more HPR, which equals more torque which equals more T/R thrust which also takes more power.

A helicopter hovering (at zero groundspeed) with a 8-KT direct tailwind may well take less power to hover then the same situation and direct headwind. This because the M/R vortex will be blown away from the T/R. Of course, if the pilot is making significant pedal inputs to hold heading, any such gains will likely be negated.