Aviation Research STC

[Adrian Weisz]

So I'm about 50 hours from TBO.  I'm thinking about some options one of them the stc to put the 470 cylinders on the e225.  Has anybody had experience with this stc?  The performance gains?   The cost of upgrade?  The hassles with maintaining a custom engine.  Would you do it again?

[Steve Zeller]

Should be done while the engine is out of the airplane for major. Don't try it as a top overhaul. Factor in cost of a completely new exhaust and maybe a new fuel and induction system.

[Andrew Hesketh]

Purchased and installed this STC on my G35 three years ago. Engine pulled and sent to G&N (Griffith, IN) for overhaul and STC incorp. G&N has experience now on doing this mod. The STC instructions are not that straight forward and many phone calls with AeroResearch to get clarifictions.  We installed steel cylinders, if I had to do it again, I would go with Nickel cylinders.  All new cylinder baffles need to be installed, I think they came with the STC.  The 470 cylinders are slightly larger and it is a tight fit on the left side of the engine compartment. We had to purchase all new exhaust system. No fuel line mods req'd. No problem with stock induction system.

Maintenance has been just like a stock engine. Had two problems that both showed up 300 SMOH: 1) premature exhaust valve guide failure on one cylinder; and 2) oil leak on one cylinder to crankcase surface (turned out to be wrong o-ring installed by G&N).

Performance is great. You can run max RPM, max throttle longer on climb out (5 min instead of 1 min). Though not officially sanctioned in STC, you can run the engine at higher RPM/MP (>23 squared) if you so wish. ARS did this as part of their development program so the engine is good for it, it is just that they did not take the time/money to get the airframe approved for higher RPM/MP, so original TC restrictions apply. Of course you get resultant higher fuel burn (nothing is for free). I consistently see 1000 fpm climb with 2 people on board, even on warm day. 350F or less CHTs at cruise but keep eye on things during climb, in fact I find that I get 500 fpm at 110-120kts, and that helps keep the CHTs down.

All in all, I am happy with the mod. Not cheap but I believe I have a better engine for it. I have pictures of the installation which I can share if you are interested.

[R. Lee Buechler]

Hi Adrian -- My aircraft was the prototype for STC qualification for this modification.  I posted the following several years ago to the Hangar Flying chat room, and offer it again for you:

First, Ia

[R. Lee Buechler]

And a little more, as an update......  

1.  As previously noted, maintenance is the same as the stock engine, but, of course, it's important to maintain the various drawings that accompany the mod so anybody working on the engine will understand what they've got.  Not rocket science........

2. I've now flown about 750 hours since I got the airplane back and the engine runs beautifully.  Uses maybe 1/2 quart of oil in a 25 hour cycle.  

3. A little after I got it back I installed the STC'd fuel injection for the E225, and got the injectors balanced.  Having taken the LOP course from Deakins, I operate LOP all the time -- cylinder head temps remain very low; oil analysis comes back very clean; boroscope shows few deposits and no hot areas; and I get about 150k at a 10.5 - 11.0 gph burn rate at lower altitudes.  Better at higher altitudes.  This can also be done carbureted if you know the routine.

4. As another poster noted, climb performance is spectacularly better.  I am currently in FL where temps are nearly always well above "standard" and I am able to achieve 1000 fpm/105k climb through 4-5,000 ft on most days.  And no cyl temp problems.

5. I used Millemium Investment Cast cyls with my install and the valve covers were extremely tight under the cowl, with some abrasion due to the tight fit.  So I swapped for TCM valve covers which fit perfectly over the Millenium cyls restoring the cowl fit nicely.  I like the Milleniums, but I think the TCM 470-Ns are just as good.....

Hope that helps......

[Andrew Hesketh]

Mr. Buechler, the fuel injection STC for the E-225-8, was that from D&G Supply Products?

[Adrian Weisz]

What's the bottom line?  The price?

[R. Lee Buechler]

For Andrew:  Yep. Fuel injection STC is currently owned by D&G Supply.  Don't know the current price.  Try www.dgsupply.com/products.html, bottom of the page.

For Adrian: For the current price, call Aviation Research at 503.668.4542.  You might also try toll-free at 888.301.9207.  Ask for either Felicia or Jerry....  they will provide the complete rundown... Web page is www.aviation-research.com/e2258.html.  

[Terry Lee]

Mr. Buechler I have researched the Aviation Research STC and have much interest in it for my D35 engine rebuild, however have you heard of anyone doing a O-470 replacement for a E225?  If not could Aviation Research do the fuel injection STC at the same time of the cylinder head upgrade in your experience?  Thanks for sharing your experience with your E225 upgrade and will help all of us trying to keep our older Bonanzas.

[Daniel Bruzzone]

I noticed that the early (straight, A, and B) models are not mentioned.  Have they been added to the STC?  Or, has anyone been successful in doing it as a field approval on these models?  I ask as my Bonanza is a straight 35.

[Donald Berlin]

I understand that the Aviation Research upgrade can not be done with the electric prop.

[Robert Siegfried]

Good Morning All,

I notice a few comments that seem to question the validity of using a higher power without making airframe changes.

The reasoning as to why this can be done is rather simple. As long as all weight limits and speed restrictions are retained, the higher power will introduce NO more stress on the airframe.

If the engine installation is heavier than the original, some beef up may be required. There is a small increase in torque forces, but so small as to be inconsequential.

The idea is the same as carrying a thirty thousand pound load on a ten thousand pound flat bed traier. The restraing straps only need to be strong enough to hold the ten thousand pound trailer to the thirty thousand pound load.

Same thing happens with the airplane. More horsepower just gives us a higher climb rate, but pulls no harder on the airframe unless we exceed the original speed limits or maximum load limits.

Make any sense at all?

Happy Skies,

Old Bob

AKA

Bob Siegfried

V35B

[R. Lee Buechler]

Quick Answers:

1. Haven't heard of an O-470 STC replacement for the E-225.  But I am not plugged into that possibility.....

2. Aviation Research did not have an electric prop plane for an STC qualification prototype -- so, as far as I know, no electric prop -- but why not just call them to confirm?  No need to guess.

3. Av Rsch or any other shop installing the modified engine could also install the Fuel Injection STC.  They are independent; the Av Rsch STC is approved for fuel injection -- the second airplane used for the testing had an injected E225 {Mine was subsequently converted}

4. I think the A & B models both are now qualified for the STC -- again, just give Av Research a call......

And -- Old Bob -- exactly!!

Lee B.

[Paul Safran]

 

....Same thing happens with the airplane. More horsepower just gives us a higher climb rate, but pulls no harder on the airframe unless we exceed the original speed limits or maximum load limits.

Make any sense at all?

Happy Skies,

Old Bob

AKA

Bob Siegfried

V35B

How about on take-off? Extreme being a soft field. If the same gross weight (mass) is accelerated quicker, the forces have to increase, especially on the mounts, keel & gear.

[Bob Siegfried$comma$$ II]

Hi Paul-

As far as additional stress caused by greater acceleration during the takeoff roll, I am skeptical. The additional g-forces due to such acceleration are pretty minimal compared to other loads on the structures involved. In the example you provided, a soft or bumpy field, the load on the keel and engine mounts is caused by deceleration when hitting a soft spot, or vertical acceleration when hitting a bump. Those loads would depend on the velocity when hitting the soft spot or bump, not on the rapidity with which that velocity was obtained.

Regards,

Bob Siegfried, II