lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> I have reviewed this subject extensively and while I agree the Thermal Wing is cheaper and lighter, I do not think it is better. I fly a Mooney Rocket with the TKS system (presently building a IVP). During the Thanksgiving weekend I flew a trip from Michigan to the Denver area and then flew from there to Wyoming in some nasty weather. I had a one hour flight to Douglas WY with a full tank of TKS fluid and conditions were not looking bad based on the flight briefing. The weather was considerably worse than forecast with icing encountered soon into the flight, and ceilings and tops doing nothing close to forecast. I ran the fluid in anti-ice mode (the lower flow rate) and was generally keeping the wings clean. Sporadically I would run into some super cooled water droplets and ice would start to build aft of the leading edges of the wing. At one point I noticed ice building on the elevator counter balance horn as well. Turning the system up to de-ice mode (high flow) not only stopped the accumulation, it removed the ice within minutes from both the aft sections of the wing and the elevator c/w horn. I see no way the Thermal wing would handle this problem. Another residual benefit of the glycol system is the prop sprayers basically keep the entire fuselage clean of ice. I have wing tips that are unprotected, so it was very easy to see what the icing conditions were like. My observations at this point may help with possible de-ice system choices. I'll start with some of the negatives. I have found the de-ice fluid to be very difficult to find while traveling and pricey. I paid $13 per gallon in Minneapolis (gladly at that point in the trip) for the fluid and have heard of guys paying up to $18 per gallon away from home. My cost per gallon was in the $7-8 range for the bulk purchase I made the day I got home. To keep the cost down you will need to stock your own fluid and carry the expected quantity for the trip. My tank holds 6 1/2 gallons and I now carry another 3 with me. At high flow rate it will empty the system in 1 1/4 hours, at anti-ice mode it will last 2 1/2 hours. The system adds about 30 lbs. to the a/c PLUS the fluid. The fluid weighs in at 10 lbs. per gallon (yes you read 10 lbs.). My Rocket has a usable of 1200 lbs., so at this point the weight penalty is minimal. I am not sure many builders will want to give up that much weight on the IV. The fluid is a consumable, it costs you every time you use it and must be refilled when used. This may sound redundant but if you don't expect icing conditions and neglect to fill the system, you will not be using it. The leading edge can get bugs plastered on them and will need to be kept clean. The fluid can be run to assist this, but not just before landing or it will weep on the hanger floor (I have noticed we no longer have mice in our hanger). I had anticipated glycol streaks on the plane requiring clean up after every use. This has not been the case, the fluid leaves no noticeable trace on the airframe. I found the Thermal wing to be much more cost and weight effective. The alternator in that system can be used (with work) as a back up charging source. It needs no re-filling, costs nothing to use, and poses no problem finding an airport for your fuel stop that stocks the fluid. I have flown in many a/c with boots and find the TKS to be far superior. It keeps the entire airframe ice free, not just the leading edges. There are no chunks of ice coming off and hitting the vertical and horizontal stab. You can tell if it is working before you get into the icing conditions, watching the fluid flow out on the leading edge. The windshield will stay pretty clean from the prop spray and the w/s spray bar works very effectively removing any accumulation. Hope this insight helps and I would discuss at length any system used on the IVP. My plane will have a de-ice system, but I have not decided what system I will use. Until someone gets a system available the decision is somewhat mute anyway. Tom Sullivan IVP Builder U.P. of Michigan LML website: http://members.olsusa.com/mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please remember that purchases from the Builders' Bookstore assist with the management of the LML. Please send your photos and drawings to marvkaye@olsusa.com.