February 2007 - American Bonanza Society

exceed 300° or what would you say thetemp range is?A: It's hard to put an hourly time onwhen to replace the mufflers, as thereare many variables such as environment,EGTs and calendar time. Most arereplaced "on condition," whenever thecone appears to be off-center in the tailpipe or, in your case, has a hole in thecenter. Mufflers should also be replacedwhen the outside diameter of the mufflershows heat distress. I would guessthat most are replaced or overhauled at1,000 to 2,000 hours.An overhauUrepair shop we bavegood reports on is Dawley Aviation inBurlington, Wisconsin (800-338-5420).I'm sure there are many others.For the heat ducting, I would useSCAT, which has a heat range of -80°Fto 350°F, or SCEET hose that has a heatrange of -80°F to 500°F. They can bepurchased from most catalog supplyhouses, such as Aircraft Spruce (877-477-7823 or aircraftspruce.com).The insulation on the outside of thisduct is to provide the maximum possiblecabin heat. If your flying is aU inwarmer climates, you probably canleave it off. -AMCalibrating CHTsJeffrey PieroseBoise. IdahoQ: My E35 has an E-225-8 enginewith a Westach six-cylinder CHT. I alsohave the original CHT in the clustergauge. There is a 100° differencebetween the two when reading the #4cylinder. I assume this is because Irecently replaced the original thermocouplefor the cluster CHT with aSpruce thermocouple, which must havea different resistance.According to the original maintenancebook, the thermocouple musthave I -ohm resistance. I am assumingthe replacement differs from this. Isthere any source of the original thermocouple,PIN 35-369125? If nOl, am Istuck trying to modify the newer onewith a resistor so the readings will be atleast close to each other?A: I do not believe we have a sourcefor the original ring thermocouple. WagAero (800-558-6868) and Chief (800-447-3408) have several different gaskettype.You can heat them and theWestach with a heat gun and use aninfrared sensor to calibrate them. -NPReplacement ignitionswitchTom PhelpsClovis. New MexicoQ: I just purchased my V35B. I'mhaving problems with the ignition switch.I have to jiggle the key before it willswitch on. Is changing the ignition switchthe answer to my problem?A: Yes, making a change seems logical.The TCM switches are availablefrom many sources, including AircraftSpruce (877-477-7823), API (800-950-01 I I) and Chief (800-447-3408). -NPErratic rpmJeff EvonsHannibal, MissouriQ: In cruise on the way home fromBPPP I noticed the rpm in my A36 waserratic, bouncing around from 2350 to2450. The engine felt fairly smooth andits prop cycled normally in the run-up.But I did notice a new streak/stain fromthe right ventlaccess panel. Any ideas?A: Was the tach indicator all that waserratic? If the engine was not audiblysurging, it could be a tach or tach cable.If the engine could be heard surging,then it could be a binding blade bearing,a governor or governor cable. -NP836TC intercoolerMike DohertyGreenville. MichiganQ: I have a 1984 B36TC that wasdelivered without an intercooler. Thereare intercoolers for this setup and I mayhave found one. Now I need a part number(or numbers) to confirm.A: The intercooler was never a Beechoption, so there is no part number perse. There have been several aftermarketintercoolers available under STC, butnone are currently supported.If you have all the parts for a specificSTC design and know which versionit is, we may be able to find the currentSTC holder who owns the intellectualproperty rights to the product.You'll have to approach that person oragency to see if they are willing to se llyou the STC, which gives you theauthority to instaU the intercooler. Ifthey do not want to sell, you may haveto engineer and flight-test the system tothe FAA's certification standard toobtain approval. - ITA36 service ceilingLorry LamsonWichito, KansasQ: Do you know the ceiling limit fora 1990 A36? I cannot find the informationin the POH.A: Although Beechcraft marketingmaterials indicate a service ceiling of18,500', there is no establ ished ServiceCeiling or Maximum OperatingAltitude for the A36 in either the PilotsOperating Handbook or the TypeCertificate Data Sheet. The limiting factoris usually the altimeter, which is typicallycertified to 20,000' unless youobtain an altimeter certified and testedto a higher altitude. -ITChanges with later A36sDave BohmerBrooten. MinnesotaQ: The Bonanza Spar AD affectsonly pre- I 987 aircraft. Also, Trade-A­Plane shows a substantial performancechange coinciding with a change to theContinental 550 engine. Since there isonly a I 5-hp difference in the 550, wasthere a change in wing design and/orconstruction in 1987? A dealer told mehe has not noticed the performancechanges (l4-knot increase in speed, a