[doctornigel]

Has anyone considered de-ice for the RV-10 (or any other RV)?

Especially the Kelly Aero electric de-ice?

I know I'm a year from getting the where I would have to make a choice, the Kelly seems like a reasonable and easily doable idea, thanks.

 

[Kevin Horton]

Has anyone considered de-ice for the RV-10 (or any other RV)?

Especially the Kelly Aero electric de-ice?

This only gives you airframe ice protection, but no prop de-ice and no windscreen de-ice. So you can't fly in known icing. If you get in any ice, you need to get out of it ASAP, and this will be true whether or not you have airframe ice protection. Once the prop ices up you will lose thrust, and you can't land very well with an iced up windscreen.

If you want to improve the odds of surviving an encounter with unexpected ice, I think turbo-charging and O2 would be a better bet. If you get in ice, the best escape is often to climb. The turbo helps maintain climb performance at altitude, and the O2 allows you to keep climbing if need be.

I've flown in a lot if ice, and I want full ice protection before I start messing with this stuff.

 

[doctornigel]

I am already planning a hot prop and pitot heat. I may go with the Eggenfeltner turbo if a few successful installs are flying when I am ready for power, and the O2 was already budgeted anyway. I hadn't thought about the windshield but I will have to look into a heated plate. I know the certified is ridiculously expensive but maybe the experimental side will have something reasonable.

I am not planning on regularly flying in ice, I know I would be a test pilot as all the RV's haven't been certified for known ice, which means more than just airframe,prop,pilot and windscreen de-icing. I just want to put it in as a back-up. I fly in the southeast which wouldn't seem like a problem, but when a cold front pushes through and I want to fly from my house in Florida to the mountains, I have to do ice planning.

Any other suggestions? Thanks!

 

[Kevin Horton]

If you are in the SE US, perhaps the heated windscreen isn't such a big deal. If the temperature at ground level will be above freezing, then any ice on the windscreen should be gone by the time you get to the runway. If you want windscreen ice protection, you might also consider a system that squirts alcohol across part of the windscreen. The Cessna C550 that I fly has a backup alcohol windscreen deice system. It only has enough alcohol to last 10 minutes, and it only clears a small strip of the windscreen, but it gives you a big enough clear area to see to land.

If you spend much time in ice, ice collecting on the elevator horns could be a problem. It wouldn't take too much ice there to give a control problem if it jammed in the gap between the elevator horn and the HS. Some aircraft have heated elevator horns for this very reason. Other ones have very large gaps ahead of the elevator horns to make room for ice on the horn.

 

[Droopy]

Ice, control surfaces, and how to get scared

I<snip>If you spend much time in ice, ice collecting on the elevator horns could be a problem. It wouldn't take too much ice there to give a control problem if it jammed in the gap between the elevator horn and the HS. Some aircraft have heated elevator horns for this very reason. Other ones have very large gaps ahead of the elevator horns to make room for ice on the horn.

This is definitely and issue with RV-8's and I would assume the other models. Don't ask how I know. Let's just say a hypothetical friend was flying in the vicinity of Klamath Falls this winter in the middle of the night (my hypothetical friend has made his own decisions and thought very carefully about single pilot, single engine, night, IFR, over the mountains.) and inadvertantly entered severe icing at about 15,000' MSL. It was like someone was spraying an ice hose at the airplane (so he says). The entire encounter was about 30 seconds. Approx 3 -4 inches of ice on the windscreen (estimated with an emergency headlight he wears at night). Engine seemed to run fine, but definite loss of thrust. Pitot froze over and GPS ground speed was used to fly. Pilot was an experienced single engine, single pilot IFR type with military fighter time and had noted the ground speed before the icing so was able to approximate what indicated should be. Unable to hold altitude (unsure if it was due to the ice on the prop or the ice on the wings/airframe). Got the divert going to the lowest MSA and then to Klamath Falls. At this point, the stick froze. I mean, it would not move and the airplane started to pitch slowly forward (trim had frozen also). A sharp thump to the stick broke the ice on the elevator (I assume on the horn, but there was no visual confirmation. More important things going on at the time.) Airplane was able to maintain 12,000' MSL (MSA was 10K). The airplane landed with the trim still frozen solid after flying the VOR approach into Klamath Falls. The windshield did clear off fairly rapidly after descending below the freezing level, but it would have been sporty if it was freezing at the surface (something to consider when doinging your preflight risk analysis.)

Bottom line. My "friend" was lucky to live through the experience, but there are some good takeaways from it.

First, icing kills. If considering setting up for known icing flight, make sure you ALWAYS have an out when that unexpected happens.

Second, experience/training. In this instance, the pilot had a lot of single pilot IFR experience. Even though he had no intention of landing at Klamath Falls, the approach was not only available, but had been looked at before the flight and was easily accessible and IDENTIFIABLE inflight, as were all the other potential diverts along the route of flight. As the only guy in the cockpit with an out of trim, partial panel airplane, you don't have the time to be flipping through a lot of pages. You need to be able to reach for anything you need by feel. Think about that when building your nest in the cockpit.

Third, flight planning. This is what the pilot used to supplement the luck that night. Don't every put yourself in the position where you need to ask ATC where you should go. Always know where you are in relation to the nearest landable surface (IFR need to factor in surface WX conditions as well as approach availability.) It was not luck that my "friend" was flying a route that took him over as many fields as possible with IFR capabilities. ATC was on the ball that night and was a great help, but as another thread lately has been discussing, you should never put your responsibilities as PIC in ATCs hands.

Fourth, priorities. Never forget AVIATE, Navigate, communicate in that order. Don't forget to fly the airplane, or the rest won't matter.

Well, I think that pretty well sums up my longest post ever...

Be careful out there playing with the weather...

John
RV-8 Flying
RV-10 Wings (on hold while unpacking from move)

 

[Kevin Horton]

...inadvertantly entered severe icing at about 15,000' MSL. It was like someone was spraying an ice hose at the airplane (so he says). The entire encounter was about 30 seconds. Approx 3 -4 inches of ice on the windscreen (estimated with an emergency headlight he wears at night).

Wow. That sounds like very heavy freezing rain, maybe. Did your friend mention how much of the windscreen was covered with ice - i.e. how close did the ice come to the canopy bow? The large droplets seen in freezing rain normally flow back a bit before they freeze, thus you get ice that covers a much larger area than is see with small droplets, that freeze where they impact the airframe.

Even if the aircraft had been fitted with a full suite of ice protection, the conditions encountered on that night are way beyond what these systems are designed to handle. Ice protection systems are designed to handle typical conditions (as defined in FAR 25 Appendix C), not extreme conditions. A system that was capable of providing protection in such extreme conditions would be require too much power (to generate heat to melt ice) that it would not be possible to fit it on most aircraft.

You make an extremely good point about being prepared to immediately go to good diversion airfields.

 

[doctornigel]

Great post, thanks.

My question is would ice protection, heated/alcohol windshield and some sort of de-ice, would that have given you more time, or a false sense of security.

I have flow certified FIKI craft and I still do something as soon as I see ice, I realized it's there to buy me time, not cure the problem.

My favorite choice is a 180 turn, cuz I know there wasn't ice there. Climbing is my second but only if it's a short trip to the top, my worst icing buildups were near the tops of the clouds right before on top

 

[Droopy]

Icing

Kevin,

Nope, I've got it on very good authority that it was very heavy rime to mixed ice. Nothing streaming aft. The airplane was right at the top of the clouds skimming in and out. OAT was in the vicinity of -0F.

Doc Nigel,

Like what Kevin mentioned, in that circumstance, I think even with ice protection, it would have just been a false sense of security. I would be very surprised if any system that a light aircraft could carry would have been able to handle that much accumulation accumulating that fast. As far as the 180, that's my favorite choice most of the time also. However, the aircraft was iced up and right back out of the cloud so fast, a 180 would have just put it right back in the ice hose again. Of course, it shortly descended right into the clouds afterwards, but there was only trace rime below.

John

 

[Kevin Horton]

Nope, I've got it on very good authority that it was very heavy rime to mixed ice. Nothing streaming aft. The airplane was right at the top of the clouds skimming in and out. OAT was in the vicinity of -0F.

Very interesting. I was initially suspecting clear ice, as you said that the pitch trim froze up. I had a hard time picturing ice running that far back before freezing, so I figured it must have been clear ice. But now I think I might understand. When you say the "trim had frozen also", I wonder if you mean that moving the pitch trim had no effect on the stick force or aircraft pitch response? This would make sense, as the elevator was frozen (probably due to ice on the leading edge of the elevator counterweight), so no matter what you did with the trim it wouldn't have the normal effect on pitch forces. In fact, it would tend to have an adverse effect on the aircraft pitch attitude, as the trim tab itself would be a mini control surface. If you trim nose up, and the elevator cannot move, you get a small nose down pitching response due to the elevator trim tab moving trailing edge down.

I don't completely understand the physics behind it, but if you have layer type cloud, the ice will be the worst just at the top of the cloud. When we are doing ice certification flight testing, and we are trying to get a bunch of ice on the aircraft, we will often fly around perhaps 20 ft below the top of the cloud layer. You actually end up leaning forward and staring up at the top of the cloud from inside it and follow the contours of the cloud as you fly through it, all the while listening to the ice specialist on the intercom as he gives a running verbal commentary on the droplet size and liquid water content his instrumentation is reading. Great fun, if you like collecting ice.

Back when I was young and immortal, I used to fly maritime patrol in S-2 Trackers. We would fly for up to 7 hours at low altitude over the North Atlantic, often in light rime icing for hour after hour. The aircraft had pretty good ice protection, so the wings, tail and props would be kept reasonably clean. But I saw 6 inches of ice on the unprotected parts of the airframe more than once. I thought nothing of it at the time, but now I realize that perhaps we were walking a bit too close to the edge of the cliff, in the fog.