| Author | Message | ||
     Kevin Dennes New member Username: Kdennes Post Number: 54 Registered: 01-2001 |
I am in need of the range markings for the Express 2000 on the ASI. This would include the flap lowering speeds as well as manouevering and VNE speeds. We work in knots in OZ but if you only have it in MPH I think I will be able to do the maths. I would also appreciate the operation markings for the engine instruments for the IO550 if someone has a list of those please. Regards. Kevin (from Downunder) | ||
| Kevin Dennes New member Username: Kdennes Post Number: 58 Registered: 01-2001 |
We are installing the EDM 800 engine scanner. I am looking for someone to advise me as to where is the best place to mount the Outside Air Temp probe please. I have asked some of the local engineers and I get a different answer from each one. It was suggested from one engineer that it could even be mounted on the lower baffle at the front of the engine near the fresh air inlet for the heater. I thought that might be a bit too close to the hot section. Still, I await your help. Regards. Kevin (from Downunder) | ||
| Gary Markwardt Unregistered guest |
Kevin: I mounted mine for an EDM700 on the front engine baffle directly behine the prop. It reads about 10-15 degrees F. high. I eliminated using the lower cowling due to the hassle of disconnecting it everytime you remove the cowling. Talking to JPI, they recommended somewhere totally away from the engine compartment. I am thinking of moving mine to the lower wing surface, possibly mounted to an access hole cover plate. You may be able to let just the very end of the temp probe protrude below the plate through a slightly oversize hole. | ||
| Gary Markwardt Unregistered guest |
Kevin: I mounted mine for an EDM700 on the front engine baffle directly behine the prop. It reads about 10-15 degrees F. high. I eliminated using the lower cowling due to the hassle of disconnecting it everytime you remove the cowling. Talking to JPI, they recommended somewhere totally away from the engine compartment. I am thinking of moving mine to the lower wing surface, possibly mounted to an access hole cover plate. You may be able to let just the very end of the temp probe protrude below the plate through a slightly oversize hole. | ||
| Phil & Margie Hodge New member Username: N410mp Post Number: 1 Registered: 01-2000 |
Kevin - My probe is the same place as Gary's, and shows the same inaccuracy. I haven't played with alternate locations, but bonding it to an aluminum plate on the underside of the wing or fuselage makes sense to me. Wouldn't want it sticking out unless absolutely necessary. If you have a fresh air intake away from the cowling it might work to put it there, too. Let us know what works, Phil | ||
| Kevin Dennes New member Username: Kdennes Post Number: 59 Registered: 01-2001 |
Thank you for your help. Larry also has been in touch and made helpful suggestions. I rang JPI and also the Australian agent and although their suggestions varied somewhat, there was one clear message from both. The probe should not be mounted anywhere near the engine bay, including virtually the whole underside of the aircraft fuselage. The prop forces mix up the exhaust as soon as the gasses leave the pipe and spreads hot/warm air over almost the entire length of the underside of the aircraft in flight. Now, unless an accurate air temp is being fed into the EDM 800 then the various readings on HP and TAS etc are going to be eronious too. Question: Does the probe actually have to be out in the airflow at all? Maybe I am wrong but I figure that if the probe were installed in the inside of the wing near to where the undercarriage leg comes out of the wing, then since there is a reasonable gap there that the temperature in that area should be the same as the outside air rushing over the aircraft. Am I thinking straight or not? Naturally, I am trying to avoid this little dangley thing hanging off the aircraft. Not only that, it could cause the aircraft to go 0.000001 of a knot slower by virtue of parasite drag! What do you think? (about the location, not the parasite drag) Regards. Kevin (from Downunder) | ||
| Tom R. Hutchison New member Username: Tomhutch Post Number: 115 Registered: 01-2003 |
I remember this same subject coming up on the Lancair Mailing List. Folks that had a NACA duct on the cowling or side of the Fuselage put the probe in the duct where it could sample he outside air. I would think in the gear leg hole would be ok if not tightly faired so air could easily enter. My $0.02 USD Tom | ||
| Bill Copeland New member Username: Cbros Post Number: 31 Registered: 09-1999 |
Kevin: The advice we got when locating our OAT probe was to expose it to the outside air temp (naturally), but not exposed to an airstream. Your idea of inside the landing gear "well" seems like a good idea. Bill C | ||
| Reinhard Metz New member Username: Reinhard_metz Post Number: 2 Registered: 03-2003 |
I have mine on the right closest in wing access cover, mounted flush. There it is away from the engine and parallel to the airflow, so there is no ram error, and it is always in shade. Seems to be right on all the time. Reinhard Metz | ||
| Jim Oyler New member Username: Midniteoyl Post Number: 3 Registered: 07-2003 |
Right behind the pitot? Tube would shield it from the airstream, and things in it. Its far out from any heat source and theres already a mounting point so you wouldnt have to worry about that .00001 knot drag either. Jim | ||
| Douglas Hoff New member Username: Dhoff Post Number: 5 Registered: 05-2003 |
While you're talking about instruments, I had Express install a King radio in my plane and have never been able to use it as it sets off the ELT when I try. Has anyone else had this problem, and if so how did you correct it? On another note, I attended the Express dinner and memorial for Larry at Oshkosh, and thought that John did a very nice job. He said that he moght stop in on his way home but apparently got too busy. We live in NW SD and are a half way point for WA and OR people so if you need an overnight on your way to or from OK let us know and we'll leave a light on. Doug Hoff | ||
| Jerry Sjostrand New member Username: Jerry Post Number: 22 Registered: 08-1999 |
Hi Doug, I had the same problem and solved it by putting a common ground to both antennas. I ran a wire and clamped it under each base. Hope that helps. Let me know. Jerry |