# Recent content by ferranrosello

1. ### Best margin above a take-off obstacle

Thank you very much, Jean C. It is a great job. I don´t know how you are calculating everything, however the results seem to be realistic. Ferràn
2. ### The catch 22 of autorotation on gyroplanes

Chuck, thank you for your explanation. Certainly 1950's Spain was very different. And the travel tour are talking about would be very close to an adventure (Spanish roads were very bad in the fifties). I hope it was a nice trip. Ferràn
3. ### The catch 22 of autorotation on gyroplanes

Eric, we know by experience in autorotating helicopters. More pitch implies lower rotor speed. The question is for Chuck experience. Why? I think that with less rotor speed the flapping action will be bigger. Is this the reason? The rotor flaps so much that you run out of forward cyclic...
4. ### I agree the gyroplane accident rate is too high;

Yes, that's correct. All aircraft are centrally registered. Ferràn
5. ### Best margin above a take-off obstacle

Ok, thank you, Jean. I agree that the energy required will be the same. However not all induced drag is transformed in rotor rpm... The efficiency depends on rotor blades angle of attack, that is to say forward air speed. It would be interesting to know how interact airspeed, rotor rpm...
6. ### I agree the gyroplane accident rate is too high;

The first thing everybody should know about accidents is that nobody is free of them. We are humans and humans make errors... All of us can make an error when we are flying... Then comes the question about who is a great pilot or a great instructor. What is the receipt. Too much complex to be...
7. ### Best margin above a take-off obstacle

Jean Claude,. I've never said nothing about parasitic drag. I've talked about induced drag... And the induced drag for a flying gyrocopter is much bigger at 58 km/h than at 75. But if the gyro is rolling below 70 km/h is still much lower. What you say about the energy transfer to the rotor...
8. ### Best margin above a take-off obstacle

Than you for your explanation Jean C. The assumption you are doing about getting airborne at 58 km/h seems reasonable. However my point is what if I don´t get airborne until being very closed to 75 km/h. Then the induced drag during the take off roll would be weaker and would use less than 50...
9. ### Best margin above a take-off obstacle

The normal climbing speed after take off is Vy. The best forward speed for obstacle clearance after take off is Vx. The wind has an impact in Vx. The air density has an impact in both. Vx is higher (not lower) at high density altitudes than at sea level. All these are facts, not a question that...
10. ### I agree the gyroplane accident rate is too high;

Thank you for your answer, TyroGyro. Of course I can help with the accident reports. In this link is the report for the august 2018 (EC-EZ1). https://www.mitma.gob.es/recursos_mfom/comodin/recursos/ulm_2018_016_a.pdf The report concludes that is not able to find the accident cause because...
11. ### Best margin above a take-off obstacle

Leaving the prerotator engaged and ease the stick back is forbidden in Ela, because the mechanical prerotation system will be destroyed. This is the only reason.
12. ### I agree the gyroplane accident rate is too high;

Hi, TyroGyro. I didn't know about the gyropedia and these, but I will check. I have a question related to your accidents report. For how many years, and how many machines in each country? I'm a gyro CFI in Spain since 2003. I have flown about 4000 flying hours in Ela and a few in Magni. I have...
13. ### Best margin above a take-off obstacle

Vx is an objective parameter. Vy too. But take-off techniques are not. What is good for a grass runway at 30ºC is not good for another situation. To take off as shorter as possible JC technique may be good (I don't know) to achieve the shortest possible ground roll. But not the shortest take off...
14. ### Pitch Question

Ok, by now is clear that the rotor disc has a positive angle of atack always. However this is not an explanation of why "why does the nose pitch down when the stick is pushed forward? " This is because the center of gravity wants to be situated always in before the rotor spinning axis. When you...
15. ### Vortex Ring State in gyros?

Hi, gents. I'm late in this post... However, the vortex ring state in helicopters implies a very fast induced flow, and this was learnt by experience. Nobody was able to anticipate in by understanding the rotors. I don`t have a suitable explanation however, gyros cannot get this high induced...