AeroElectric-List Digest Archive

Wed 11/09/11


Total Messages Posted: 4



Today's Message Index:
----------------------
 
     0. 12:22 AM - Reminder (Matt Dralle)
     1. 03:59 AM - Re: Wiring a Skytec Starter (Bill Watson)
     2. 09:29 AM - Re: Wiring a Skytec Starter (Robert L. Nuckolls, III)
     3. 02:56 PM - UPSAT Transponder (Charles Brame)
 
 
 


Message 0


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    Time: 12:22:08 AM PST US
    From: Matt Dralle <dralle@matronics.com>
    Subject: Reminder
    Dear Listers, Just a quick reminder that November is the annual List Fund Raiser. The Matronics Lists are 100% member supported and all of the operational costs are provided for my your Contributions during this time of the year. Your personal Contribution makes a difference and keeps all of the Matronics Email Lists and Forums completely ad-free. Please make your Contribution today to keep these services up and running! http://www.matronics.com/contribution Thank you in advance! Matt Dralle Matronics Email List and Forum Administrator


    Message 1


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    Time: 03:59:01 AM PST US
    From: Bill Watson <Mauledriver@nc.rr.com>
    Subject: Re: Wiring a Skytec Starter
    I have the Vans supplied LS starter for the IO-540 on my RV-10. After initial experience with the LS starter and much consultation with other RV10ers, I plan to replace it with an NL type starter. Why? The LS gives me a 'saggy' kind of turnover. If the battery is anything but topped off, and OAT is 60+, it is likey to stall out before a full revolution. I can generally 'bounce' the prop and get it to turnover the 2nd time. It will turn it for a long time (don't ask) but that's a function of battery capacity. I thought it was the Odyssey 680 battery - perhaps uncared for, worn out, or recharged badly. I learned a lot about battery care and maintenance but after much testing I discovered that all (4) batteries I've accumulated are serviceable and 2 perform as new. I'm told that the LS starter uses permanent magnets in it's construction. Light weight yes but less 'snappy' in it's performance. The NL starter is not much heavier and performs like the older, heavier starters. I'm still running with the LS - I have a robust 2 battery electrical system where I can generally use just 1 for start but can go to 2 if it won't go. But as cooler temps approach, I will be swapping it out for the NL very soon. There's lot's about this on this forum and the RV10 forum. Of course the -540 is a bit bigger than the -360 but I'm sure it is even a factor. I understand that Sky Tec will exchange it if it is unused but I don't know.... I'll just have a backup starter on the shelf. Bill "just made my annual Matronics contributribution because of stuff like this" Watson ('saggy','bounce', and 'snappy' are trademarked technical terms limited to use within the community of amatuer builders and tinkerers) On 11/8/2011 5:33 PM, Peter Pengilly wrote: > <peter@sportingaero.com> > > Bob, > > I would swap the starter out for an NL type (much better starter at a > small weight penalty) and use the wiring that Sky-tec recommend. The > weight saving from eliminating the starter solenoid is negligible. > > Peter > > On 08/11/2011 21:49, Bob Falstad wrote: >> --> AeroElectric-List message posted by: Bob Falstad<bobair@me.com> >> >> Bob, et al, >> >> A friend of mine is building an RV-8A with a Lycoming engine bought >> through Van's. It came with a Skytec starter, P/N 14912LS. >> >> Skytec recommends wiring it without a separate starter contactor. >> Apparently, the solenoid that pushes the pinion gear out to engage >> the ring gear also can act as the starter contactor. Van's shows >> wiring this starter with a conventional, separate, starter contactor. >> >> Skytech shows wiring schematics/diagrams for each approach at >> http://www.skytecair.com/Wiring_diag.htm (see Diagram A) >> >> What are the pros and cons of each approach? What experience have >> listers had with each? (My friend does plan on using a push-to-start >> switch, not a conventional key switch.) >> >> Best regards, >> >> Bob Falstad >


    Message 2


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    Time: 09:29:30 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Wiring a Skytec Starter
    At 05:54 AM 11/9/2011, you wrote: > >I have the Vans supplied LS starter for the IO-540 on my >RV-10. After initial experience with the LS starter and much >consultation with other RV10ers, I plan to replace it with an NL type starter. > >Why? The LS gives me a 'saggy' kind of turnover. If the battery is >anything but topped off, and OAT is 60+, it is likey to stall out >before a full revolution. I can generally 'bounce' the prop and get >it to turnover the 2nd time. It will turn it for a long time (don't >ask) but that's a function of battery capacity. Some years back, we explored the performance difference between various offerings of starters with the goal of explaining perceived performance differences. Back about 1990, the BIG thing was WEIGHT. The bad dog in the pack was the Prestolite series of starters which were retreads from 1940's automotive. They were indeed heavy . . on the order of 15-17 pounds. OBAM aircraft owners were making successful adaptations of modern, and much lighter starters to the aircraft engine. The flying mags carried a number of how-to articles. About that time, one Bill Bainbridge at B&C began mulling over the options and tradeoffs . . . not for an adaptation . . . but a brand new starter that would not only be lighter but performs better. The lighter part wasn't difficult. But performance was a little more challenging . . . along with designing a casting that could stand up to the occasional kick-back. The B&C starters have always been wound-field motors geared to run at higher than pinion rpm by appropriate gearing. Recall that HP = (torque X rpm). Allowing the motor armature to run faster reduces the output shaft torque required to produce the desired power. Recall too that a motor has a sort of bell shaped efficiency curve . . . zero rpm (stall torque) is ZERO output power. Max rpm (free running) is also zero output power. Someplace between zero and max rpm on the performance curves, the motor produces MAXIMUM power output. The best performing starter would be the beneficiary of trade offs for weight and performance. Bill prayed over that product for a couple years before he drug the first production to OSH . . .I think it was about 1991. Then came the field testing . . . and the toe stubbing. Field tests were encouraging. Reports from customers on performance were always glowing. The downside of the lighter castings was a vulnerability to poorly timed mags and kickback. There was a significant number of returns for broken castings. Sometime early in the life of the B&C Lightweight, some webs in the castings were strengthened. The really cool thing was that the starter was proven superior to any production starter offered on ANY engine in Lycoming's stable up through the 235 to 720. Once market viability of a modern starter was demonstrated, the wanna-be's had to compete . . . on price and to a small extent on weight. Unfortunately, I've never seen a lucid comparison of performance of the various starters. Some years ago, I wrote to biggest players asking if they would loan exemplar samples of their product line to be placed on instrumented test stands to characterize all significant performance points. Nobody but B&C offered to make their product available for such studies. So here we are, 20+ years later with no real comparative numbers that would assist the cogent buyer in making their own return on investment decisions. Unfortunately, I've got so many things on my plate that it would be pretty dumb to offer to do that again. I did have an offer about 10 years ago from a publisher to finance such a study. I agreed . . . then didn't hear from them again. In today's economic state, prospects for a similar endeavor are somewhere between zero and none. Nonetheless, it would be a VERY interesting study. Bottom line is that there ARE starters which will pretty much spin any engine at 100 rpm (3 blades per second) with a reasonably maintained battery and properly wired airplane. Bill and I drove to some guy's hangar down in OK many years ago to hook Bill's new 10 a.h. battery offering to a IO-540 fitted with one of Bill's starters. We did 5, 15-second cranking cycles in a row. The 5th cycle didn't not seem to be taxing the battery. Did detect some slowing which was a product of battery depletion and motor heating . . . but the cranking rpm was till quite energetic. Unfortunately, none of these starters will be grouped at the lowest cost end of the price spread. Further, wound field starters will always perform best for cold-day and hot-start scenarios. There are some issues common to ALL modern starters fitted with two-stage pinion-engage contactors. See: www.aeroelectric.com/articles/strtctr.pdf This article does NOT touch on special considerations for solenoid-contactor variations such as the Sky-Tec multi-voltage, NL starters. The Sky-Tec posting at http://www.skytecair.com/Wiring_diag.htm is an illustration of how many recipes for success can pile up to confuse the OBAM aircraft builder. Bottom line is that the wiring first offered by yours truly and published in B&C documents was based on a study of starters, solenoids, styles of starter switches, and commonality with the vast majority of airplanes already flying. It would be just fine for all but the specialty starters . . . in fact, just fine for the NL starters when the jumper is properly configured for system voltage. Another bottom line is that to my knowledge, there are no incidents where a B&C starter owner found it advantageous to swap out for any other brand based on inability to perform-as-advertised on any engine. Bob . . .


    Message 3


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    Time: 02:56:47 PM PST US
    From: Charles Brame <chasb@satx.rr.com>
    Subject: UPSAT Transponder
    Don, The SL70 altitude readout is always based on an altimeter setting of 29.92. That is true of all transponders and you cannot change or vary that setting. The readout on the face of the SL70 is the actual altitude the transponder is sending to ATC. When ATC receives the 29.92 based altitude, it is converted to the local altimeter setting for the area where you are flying. Thus, ATC should read the same altitude as your correctly set baro altimeter. If you set 29.92 in your baro altimeter, on the ground or in the air, it should read the same as the indication on the face of the SL70. If your baro altimeter is anything but 29.92, the SL70 SHOULD read something different than the baro altimeter. You said that ATC reports your altitude correctly as per your steam guage, which tells me that your SL70 is working as advertised. If ATC reports your altitude as something other than what your baro altimeter is showing when set with the proper setting, you may have a problem that can be corrected by adjusting the altitude encoder. That is best done by a technician during the bi-annual altimeter certification process. Charlie Brame RV-6A N11CB San Antonio ------------------------------------------------- > > Time: 10:34:07 AM PST US > From: DCS317@aol.com > Subject: AeroElectric-List: UPSAT Transponder > > > My UPSAT transponder Apollo Model SL70 gives Air Traffic Control the > accurate altitude compared to my steam gauge altimeter and Chelton/ > Grand Rapids > > Technology units. However, the INDICATION on the face of the > transponder > is 300 feet off. Therefore not a problem with IFR, i.e., ATC gets > the right > altitude from interrogating the transponder (I've asked ATC numerous > times), but I'd like the readout on the front of the SL70 to agree > with my > other altimeters. > > Any easy do-it-myself fix? > > Don




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