---------------------------------------------------------- Commander-List Digest Archive --- Total Messages Posted Wed 02/09/05: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:29 AM - Re: Merlyn 320 Conversion (nico css) ________________________________ Message 1 _____________________________________ Time: 08:29:32 AM PST US From: "nico css" Subject: Re: Commander-List: Merlyn 320 Conversion --> Commander-List message posted by: "nico css" Great review, Larry. That sounds like about the right config for the B. It appears to rival the speed of the Aerostar a bit with the comfort of the Commander. Nico ----- Original Message ----- From: "Larry Wokral" Subject: Commander-List: Merlyn 320 Conversion > --> Commander-List message posted by: "Larry Wokral" > > >Can you tell us more about the Merlyn 320 conversion? In the Mirage > installation, those engines were blamed for excessive vibration, oil > consumption and temperatures. How does it behave in the 500B? > > Jimmy> > > Scott Dickey, who also has one, described it here several months ago and > probably did a better job than I can. Here are the basics. > > Hugh Evans calls it a "Merlyn 320 Shrike Conversion." The 500B, S, & U are > currently eligible for this new STC (#SA01212SE). Mine was the prototype, > although Scott's was completed first. The original engines are removed and > replaced with Lycoming TIO540AE2A(MC) engines. These are wide deck engines > with a 2,000 hr TBO that were originally rated at 350 HP. He buys them from > the company in Spokane that removes them from the Malibu's that change to > the turboprop STC. Mine had around 200 hours each since new. He then puts > new Millennium up exhaust cylinders on them and adds his single turbocharger > and exhaust setup. The Hartzell HC-C3YR-2UF/FC8468( )-6R props are required, > so they have to be purchased if the plane hasn't already been upgraded with > them previously. I elected to order them with the electric hot prop kit. > > The turbo waste gates are throttle linkage controlled and, since the turbo > is mounted high, it requires no scavenge pump. The 70 amp alternators from > the Piper installation are reused as are several other items including > remote mounted oil filters, better air oil separators, the pressurized > magnetos, and the electric hot prop assemblies if requested. He installs all > new fire sleeved oil hoses and new engine lord mounts. > > The engines are derated to 320 HP at 38"/2500RPM. The maximum prop RPM is > 2500. 42" MP (maximum intermittent) is allowed up to 18,000'. This gives an > unofficial 15 more HP (approximate) for a high performance takeoff (in fact > the pop off valve is set to allow this extra boost). Since the engines were > originally rated at 350 HP, I don't expect any problem from doing the > 42"/2500RPM takeoff, and I often do. The new single engine service ceiling > (at 7,200 lbs.) is 16,000'. Scott says he gets 200 KTAS in the upper teens > at 75% with about 36 gph. I haven't been up there yet, but I've been getting > over 170 KTAS down low on local flights at 26"/2200 RPM (about 60%) with a > burn of under 30 gph and TIT leaned to 1640 (about 65 ROP). The CHTs have > always been well under limits (although its been cold here), I've seen no > vibrations, and the engines seem to keep 9 quarts (when I put in more, it > blows it out). > > The conversion includes a gross weight increase to 7,200 lbs. (up from the > stock 6,750 lbs.). The extra weight of the new components is about 100 lbs., > so you actually get a net increase of about 350 lbs. You can also opt for > his 70 gallon fuel increase kit which takes the allowed gross weight to > 7,400 lbs. (any weight over 7,200 lbs. must be in fuel). I have not yet > added this, but I'm considering it. His certification has some other options > too. I elected to take out the original fuel flow gauge and replace it with > a Shadin Digidata fuel flow/ADC as the new primary. I believe that Scott > went with a Shadin Micro Flow. Neither of these are approved by Shadin as > primary fuel flow replacements (simply due to the lack of demand), but Hugh > got them approved as options under his certification. > > The new performance is really awesome compared to stock. My C177 Cardinal RG > was turbonormalized, and I had gotten used to flying high and from high DA > fields without much thought. I missed that ability with the Commander. I > first tried to get someone to do a simple turbonormalized system on the > stock engines, but didn't get any interest - even from Merlyn initially. > (Now, Merlyn does a turbonormalized system based on the work he did for the > 320 conversion. He has installed 2 or 3 of those). After several discussions > with Hugh, he decided that a reduced version of his already STCd Merlyn 350 > just might be a good idea. It all evolved from there. > > Larry Wokral > >