I already passed today! but good questions.
1) 9000 AGL: due to certification requirement to perform an emergency descent and landing within 5 minutes (fire)
2) Hadn't thought about this too much but I presume it had to do with maintaining a minimum main rotor RPM with full down collective during autorotation, but according to the POH it's for weight and balance. I did a W&B for my ship with a 125 lb solo right seater and it's out of lateral CG if you just fuel up the aux (unlikely situation I know). Unfortunately I will never have this problem, thus my training ship is the R44 instead of R22.
3) To minimize the risk of mast bumping?
I'm sure there are better answers and am eager to hear them!
1. correct.
2. yes, oddly enough. That bird can actually be too light to where it can’t build lost Nr in an auto. Crazy indeed.
3. true. How does that occur in that situation?
Why is there a 9000’ AGL max altitude for the R44?
What is the purpose of the minimum gross weight for an R44?
Why are low-G cyclic pushover maneuvers prohibited?
like you I have nothing to compare to but I think it’s a good ship for its mission. I don’t care for the T cyclic but it’s not a deal breaker.
My only serious gripe about the R44 is the engine. The IO-540 is a great power plant in the nose of a Cherokee 6 or Cirrus but when you stuff it in the belly of a helicopter you can just expect trouble. The squirrel cage fan keeps air over the cylinders but the rest of the engine just bakes.
I wouldn’t buy one for that reason alone.
Ya, the parallel valve 540's go up to 260hp when spun at 2700rpm and with 8.5:1 pistons. They more or less reduce one or both of those to derate the engine. 225/205 is the lowest I've ever heard of them being derated. Mine runs pretty cool at such a low power setting.Yeah, I was only flying the Raven 1 with the carb'd O-540 which is pretty massively derated to 225 HP takeoff/205 HP continuous in that helicopter. It's my understanding that motor can make 260 HP in other applications (granted I flew an O-540 in a R182 that was only rated to 235, another de-rated situiation iirc). Plus Alaska where it was usually ISA -20 to -30 C.
But, owning a 44 is way out of my budget and will be for a long time. The 2200/2400 overhaul combined with the maintenance costs are just too much sadly, for just about any airline employee I would think (barring some kind of partnership/leaseback money making situation to offset costs). I will have to be satisfied with renting one, despite the costs of quarterly checkouts (I think that might be a good idea in a robbie though).
So they just de-rated via manifold pressure then? And count on the human to do so?Interesting. The R44 Raven 1 motor is listed as an O-540F1B5 variant which has a dry weight of 400 lbs according to textron. Maybe the ones in the R44 are further lightened. Mixture is a "don't touch" control except during before start and shut down. Carb heat stays on almost all the time until it gets below about -15 C OAT or above 30 C. I've heard some people say they might lean for max performance takeoffs above 5000 ft DA, but there is no EGT gauge.
It's de-rated for increased reliability, weight savings, and "more consistent performance across various altitudes" supposedly (idiot-proofing?). Takeoff power limit is determined from a chart prior to every takeoff. You can pull full power in an emergency though, obviously. Hard to really know how much performance you could get on a cold day at sea level if you did. I'm guessing a lot. Not sure of the implications for the tail rotor if you did. Other parts of the transmission system might be part of the reason for the de-rate as well.
So they just de-rated via manifold pressure then? And count on the human to do so?
Looking up the F1B5 on lycoming's page, it's rated at 260HP at 2800rpm. It's got a different crankcase, different mags and different studs for engine mounts. So the 225/205 are airframe manufacturer limitations.
I'm sure your MAP gauge read's in .1 in Hg increments, the lines are large enough and the needle steady enough to actually set that.Yep. This is in the cockpit and POH. It's on the checklist to look at it before engine start (OAT gauge is required equipment, but how accurate is it if you just pulled your machine out of a heated hangar ). You're allowed to add an additional 1.5" to the limits with full carb heat on. There's a redline on the manifold pressure gauge at 26.3" but there are debates about whether it really has any meaning. So it's all on the pilot not to exceed the limits.View attachment 51830
True, I just round down to the nearest Inch generally. If I'm in a confined area max performance takeoff and feel like it might start to settle into vortex ring state, I pull the power I need to maintain a positive rate of climb before a sink rate develops (hopefully the OGE hover chart prevents you from needing to exceed takeoff power, but I'd much rather exceed than get vortex ring obviously).
I agree, I would pick another LZ if the area is soo confined I couldnt move 5ft any direction. My shop requires at least 1/3 rotor disc distance for LZ area.
On a side note, I know I dont post on here often, but I am happy to try and answer any rotor questions anyone has. I know @MikeD and a few others are helo guys and more active on here than myself, but I'm happy to help as well. Currently back in HEMS, from flying 767's at Atlas but hoping to go back to 121 pax after the corona scare settles down
I would agree with you on the R22, I’m not a huge fan. The R44 and R66 on the other hand auto very nicely and almost JetRanger like...notice I said “almost” haha!The R22/44 scares me. Low inertia rotor systems and single engines shouldn't go together. Even with 4000 RW hours I wouldn't trust my reaction time to respond to an engine failure in the R22. Also what's up with the teetering flight controls? Does the instructor just get used to flying with his/her hand up in the air at a weird angle?