stevecampbell Posted July 2, 2012 Report Posted July 2, 2012 Hi Everyone, I've been reading MooneySpace for a while now and just got into a 4-way ownership on a 1978 M20J about a month ago at KIWS. I'm now getting a full taste of the ownership experience. I've got a couple of questions I'm sure someone knows the answer to. 1) Does anyone know the part number of the spring that holds to jump starting (aux power port) cover door closed? 2) Our gear retract airspeed safety switch is also INOP. We've been having to override it with the red button to get the gear to retract. Does anyone know the part number for this switch? 3) also just did a GPS averaged speed at ~4200' at 2500rpm full throttle. Flying all 4 directions, the GPS ground speed averaged to 152 kts. This seems really slow, as the mooneypilots review article showed 160 kts. The tanks were around 1/2 full and there was around 320 lbs of pilots in the front seats. I'm suspecting rigging and/or sagging engine (the engine IS not properly shimmed per Don Maxwell's article). Any comments? 4) while doing the GPS speed test, the hottest CHT was getting to around 400 F, cowel flaps closed. The air temp was likely around 20C. Do you M20J pilots see the same CHT's on a summer evening in the south at 2500/25"? Thanks for the help, Steve Quote
Parker_Woodruff Posted July 2, 2012 Report Posted July 2, 2012 Steve, The aircraft performance and engine temps will largely be dictated by how you run the engine. What altitude were you at to achieve those numbers? Also, do you have a digital fuel flow indication? If you are sitting there at 50 degrees rich of peak EGT, 400dF is plausible. I suggest going and flying at the same altitude, wide open throttle, 2500 RPM, and lean to about 9 GPH. That should put you safely Lean of Peak. I imaging your cylinder head temps will be lower with the cowl flaps closed. Other things to check are the baffling. Your true airspeed while at 9 GPH LOP should come around 148-155 KTAS. When I bought my M20K, it flew straight but was misrigged until Maxwell went and got it rigged correctly. Just because the plane flies straight doesn't mean you aren't losing some speed somewhere! Sorry, can't help on the part numbers Quote
stevecampbell Posted July 2, 2012 Author Report Posted July 2, 2012 The altitude was 4200' and the mixture was leaned to 100 ROP (~11-12 gph). Yes, flying LOP would definitly get the temps down (I'm a big fan of it), but the way the other members fly the plane and the way its billed, it doesn't make sense to loose the speed. Steve Quote
stevecampbell Posted July 2, 2012 Author Report Posted July 2, 2012 that's funny.. just posted reply but different RE: subject came up.. Anyway, mixture was 100 ROP at 4200' altitude. BTW, what did Maxwell charge for rigging? Quote
Lood Posted July 2, 2012 Report Posted July 2, 2012 In my personal opinion, anything higher than 380 deg on CHT is too high and from what it seems, most J models don't really go faster than about 155kt. Quote
Parker_Woodruff Posted July 2, 2012 Report Posted July 2, 2012 Quote: stevecampbell Anyway, mixture was 100 ROP at 4200' altitude. BTW, what did Maxwell charge for rigging? Quote
DaV8or Posted July 2, 2012 Report Posted July 2, 2012 The sweet spot for NA Mooneys is at about 7-9,000 ft. Try your test again higher up and you'll probably get closer to the 160kts. Too bad about your partners. You may end up with motor work if they don't do ROP right. It's OK to run ROP, just either run 125 degrees ROP, or throttle back to book 65% or lower. 400 deg. CHT is considered high these days and it is suggested that you should be doing something to lower that number if you see it. Of all the issues that I imagine come up with partnerships, I would think that engine management would be the most important. Seems like all partners need to be on the same page, that way when something happens to the engine, there's no finger pointing. As to your part numbers, an MSC will help you, but perhaps someone here has the Mooney IPC (Illustrated Parts Catalog) for your plane that they can share with you. Then you can look up the part number for any part on your plane. You need IPC MAN226 I believe. I don't have a J, so what I have won't help you. Quote
stevecampbell Posted July 2, 2012 Author Report Posted July 2, 2012 DaV8or, Thanks for the IPC number.. I was wondering where we look those up. I like to keep CHT's under 380, better at 360. According to the mooney pilot's review article, it should do 160 kts at 4500 ft at 2500/25". One of the workings of the partnership is that everone would have to fly LOP, then we could reduce the fuel cost per tach hour charged to each member. We could do the "everyone buy your own gas" thing, but our airport has substancial weekend fuel rates that make it nice to only fill up on the weekends. Quote
jetdriven Posted July 2, 2012 Report Posted July 2, 2012 Quote: Lood In my personal opinion, anything higher than 380 deg on CHT is too high and from what it seems, most J models don't really go faster than about 155kt. Quote
Txbyker Posted July 2, 2012 Report Posted July 2, 2012 Steve, where's your base? I am at Hooks. I see 163 TAS corrected for temp and alt at 8000 ft. with stable air. I find it takes a while to trim out and obtain the cruise (5 mins or so before nose trims lower). I run upper 300's CHT on these record breaking heat days around TX but only as a peak. I avg around 320's CHT. Quote
jetdriven Posted July 2, 2012 Report Posted July 2, 2012 Russ, how do you arrive at that TAS value? Quote
stevecampbell Posted July 2, 2012 Author Report Posted July 2, 2012 Byron, our hottest is #3. I'll play with it a bit more. Russ, we're at IWS. What power setting are you at 320 CHT? How is your spinner/ cowel interface...Centered? Our spinner is lower (and ram air inlet) than the cowel, but I haven't checked whether the cowel is sagging... Steve Quote
co2bruce Posted July 2, 2012 Report Posted July 2, 2012 I have also owned a M20J and I think 155 kts at 10.5 - 11 gph is about right. I know there are those on the forum that can get 160 (I've even heard 170) but color me skeptical. Quote
Parker_Woodruff Posted July 2, 2012 Report Posted July 2, 2012 My M20J could do between 164-167 KTAS on the ROP side. Other than a couple times to see how it would do, I never ran it ROP. It was always 150-155 KTAS when LOP and it seemed to do the best at about 7000' when the OAT was about 10C. Quote
OR75 Posted July 2, 2012 Report Posted July 2, 2012 P/N for the spring is: 916008-009. I don't know how specific it is to Mooney. As far that gear safety switch, are you talking about the one tied to the airspeed indicator ? I once got 175 knots but I cannot remember if it was ROP or LOP and whether the spinner was on or off ... Quote
Txbyker Posted July 2, 2012 Report Posted July 2, 2012 Quote: jetdriven Russ, how do you arrive at that TAS value? Quote
jwilkins Posted July 2, 2012 Report Posted July 2, 2012 Quote: stevecampbell Hi Everyone, I've been reading MooneySpace for a while now and just got into a 4-way ownership on a 1978 M20J about a month ago at KIWS. I'm now getting a full taste of the ownership experience. I've got a couple of questions I'm sure someone knows the answer to. 1) Does anyone know the part number of the spring that holds to jump starting (aux power port) cover door closed? Thanks for the help, Steve Quote
Kwixdraw Posted July 2, 2012 Report Posted July 2, 2012 There are some things beside rigging that can cost you some knots too. Get her up on jacks and check the gear door and cowl flap rigging. These can save you 3-4 knots pretty easy. Quote
stevecampbell Posted July 3, 2012 Author Report Posted July 3, 2012 as far as the gear switch...yes.. it's the one tied to airspeed that we need. I haven't seen the old switch, and am wondering if it just needs its contacts cleaned and could be repaired, or if we need to buy a new one. Quote
stevecampbell Posted July 3, 2012 Author Report Posted July 3, 2012 BTW, does anyone know much much of a speed penalty the step is ? Quote
DaV8or Posted July 3, 2012 Report Posted July 3, 2012 Quote: stevecampbell BTW, does anyone know much much of a speed penalty the step is ? Quote
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