my rotors seem to turn too slow

[Redbaron]

my rotors seem to turn too slow! my rotor hawks turn slow! I'm scared their too slow for turbulence! I'm off at 25 mph and I can almost look up and count how many times they turn! is this normal? hey doug how many rpms did your bee make?

[Timchick]

Hmm. That's one of the things your instructor can help you with.

[Earthboundmisft]

Aw heck, you can figure it out on your own, dont worry about what anyone thinks.

[Redbaron]

Hmm. That's one of the things your instructor can help you with.


maybe I should eat more redbaron pizzas? its crazy how fast this thing will come off with a little wind. I can levitate tim on 40 hp with a slight breeze! rock back with a 10 mph wind and fly at 10 mph ground speed! :)

[Redbaron]

ha, I only hope my bee is stable! if instructors flew stable gyroplanes they would be livin off of creek water and balogna sandwiches :)


thanks buddy, love the smart ass comments lol

Aw heck, you can figure it out on your own, dont worry about what anyone thinks.

[Resasi]

Guess whose just taking the piss.

[lanichol]

There had been several threads over the year on building rotor tach.

[Redbaron]

thanks for letting us know your pissing! I've been playin with my bee today! the bees disc loading is so light it inspires too much confidence!



Guess whose just taking the piss.

[Resasi]

Hey Jeff guess where the Red Baron ended up?

Smokin hole in the ground. :sad:

He thought he was pretty good too.

[Chuck Roberg]

Date: September 30, 1999 08:27 AM
Author: Mike Schulman (rotors@uswest.net)
Subject: $15 (or less) Rotor Tach

I've had several people ask me about this so I decided to post it. This rotor tach is cheap, dependable and accurate. There are several places that you can get this tach. I got mine at Wal-Mart but you can also get it at Target, K-Mart and a lot of bicycle shops. It is the 5 function Cyclocomputer made by ACE Model # 810-230. It is sold under various brands but it is always identified by the Model #. It is powered by a small battery (with auto on-off) The directions are very simple and easy to set. It comes with about 6' of cable and you will need to splice in a longer section - I have lengthened my cable to 10 ' and it still works. You mount the magnet to the prerotator ring or to the rotor head, and then you mount the pickup where the magnet will pass within 1/4" of it. Read the instruction for setting the cyclometer and set it for metric "L" with the number 1667. (If you prefer to use two magnets, space them 180 deg apart and set it with the number 833). Mount the digital readout where it is convenient --and there you have it!! The read out will show a decimal point right before the last digit-just disregard it. The unit is accurate to within five (5) RPM. (BTW this is not my idea Tom Sled told me about it!!)

Mike

[WaspAir]

OK - since some smart-aleck comments are already accepted on this thread, let me vent about a pet peeve for English usage.

I have never seen a gyro with "rotors".

Gyroplanes have one rotor, period. It can have 2, 3 or 4 blades, of course, but together those blades make a single rotor.

Helicopters typically have only two rotors: a main rotor with 2 or more blades, and a tail rotor with 2 or more blades. The total blade count can be high (e.g., five main and four tail), but that's not the same as 9 "rotors". A CH-47 has two "main" rotors.

For reasons that elude me, only gyro people are ever heard to talk about their "25 foot rotors" as if each blade is its own rotor; helicopter people don't seem to abuse the words that way.

[StanFoster]

Waspair- Good point. If I say my rotors are turning too slow....they both are since the main rotor and the tail rotor are geared together.


Stan

[Resasi]

Not really picky and I agree.

I, certainly guilty as charged, you are quite right. Have taken note and will try to do better.:)

I would tend to say wings rather than wing, although in the case of a biplane and referring to the top wing, obviously a single structure.

[PW_Plack]

my rotors seem to turn too slow! my rotor hawks turn slow! I'm scared their too slow for turbulence! I'm off at 25 mph and I can almost look up and count how many times they turn! is this normal?

Red, apparently not scared enough to make fear serve its most useful role.

This is one of those areas where your need to be a rebel makes your question hard to answer. Nobody can tell you if they're too slow until you tell us your actual rotor RPM.

The 'Bee is intentionally designed with light blade loading, so it can use a 40 HP engine. As in many parts of life, that brings the risk of too much of a good thing. There are at least four ways to find out if you have inadequate rotor RPM:

(1) Spend the $15 and put a tach on it...

(2) Have the machine flown by someone with enough experience to have developed a feel for rotor RPM without the need for a tach...

(3) Use publicly available formulas to determine if you have too much blade for the machine's takeoff weight...

(4) Instruct the people you leave behind to read the NTSB report on probable cause. This one's not often reliable, because the NTSB has little background in gyroplanes, but historically it's a popular choice, despite the open-loop nature of the process.

[phantom]

you can check rotor rpm with a photo tach or have someone take a photo of you in flight with a camera that the shutter speed can be set to a known value and you will be able to see how far the tips have traveled while the shutter was open, some video cameras have the same feature, I had a hitachi that I could set to stop a rotor or prop and it was great for tracking and hunting down viberations as I could see that at some power settings and speeds the prop was going out of track due to passing behind the seat and up into clean air again.

[C. Beaty]

If the thing flies, if the rotor can be hand started and if the stick isn’t jammed up against the forward stop, the rotor is operating normally.

[Passin' Thru]

If the thing flies, if the rotor can be hand started and if the stick isn’t jammed up against the forward stop, the rotor is operating normally.

And THAT is the whole matter in a nut shell!!:D

[EI-GYRO]

On the other hand, if you have no clue what your RRPM is,
and no clue what it should be,
You may be clueless. :)

While one would not wish to discourage questions in any way,
some questions are arising lately, from people already flying and/or testing gyros,
that are VERY basic.

If you insist on self-training, you owe it to yourself, your family, and others,
to take it seriously and read the books FIRST.

[PalmPilot]

Congrats on your build...

But,

Training and get a Rating, will be one of the most exciting and rewarding times. Met with a lot of cheer's and congratulations!!! Please, do not be deprived of that, ahead of time.

[LGoodhind]

So the critical thing is the "stick isn't jammed against the forward stops" part? I had thought the back and forth on low disk loading over the years was related to increased stress on the blade root (slow down and coning increases along with related stress) but in reviewing this thread it seems like the major concern was increased pitch sensitivity from a shallow angle of attack. (http://www.rotaryforum.com/forum/showthread.php?t=9404)

[Timchick]

What size blades, how much is the all up weight and what altitude are you flying at?

[C. Beaty]

The rotor’s thrust vector, at a given airspeed, depends upon its drag/lift ratio. If the rotor drag/lift ratio is 0.2, then its thrust vector, the axis of the tip plane, points rearward by atan of 0.2; 11.2 degrees.

The cyclic flapping or blowback angle depends upon mu, the ratio of forward airspeed to rotor peripheral speed. The slower the rotor, the greater the blowback angle and the more forward the stick to orient the rotor thrust vector to its proper position.

I’ expect Pete Johnson, along with a host of others cranked his Rotordyne blades to the highest pitch angle at which he could get them to autorotate. That done, maximum forward airspeed is ~20 mph with the stick jammed up against the forward stop. A gyro set up that way climbs with more power and descends with less power, all at 20 mph with the stick on the forward stop, leaving an impression of screwing itself up and down with the throttle.

[bones]

If this guy is not pulling all our chains, he is one lucky(so far) SOB