Airworx 180HP O-300 STC

How to keep the Cessna 170 flying and airworthy.

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TFA170
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Re: Airworx 180HP O-300 STC

Post by TFA170 »

GAHorn wrote: They’d have to take your engine with and without the polished ports with absolutely no other differences in atmosphere, temp, and dozens of other things exactly equal…to make that claim.
Actually, most modern dynos correct to standard day conditions...so every run is apples to apples from an atmospheric perspective. Older mechanical dynos did not, but most operators have a "cheat sheet" (or did back in the day) to make approximate corrections to standard day.

Regardless, increasing VE generally increases HP. I agree with you that any HP/TQ measurement needs to have an RPM associated so as to make an apples-to-apples comparison over original. The actual dyno run chart would be even more useful overlaid on an original chart.

Port work can be tailored for RPM range though, so given someone who knows what they're doing for specific applications, like Lycon, it is realistic to assume the port work is tailored for the anticipated RPM range and not maximum RPM necessarily.
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jklaerner
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Re: Airworx 180HP O-300 STC

Post by jklaerner »

For those interested in this possible STC, see the latest announcement below from Airworx. I know many are in favor of this as well as others who are not. I am just posting information so please don’t shoot the messenger!!!

“We would like to share some updated info on the Continental O-300 Hp upgrade. we now have a completed and approved data package that will follow the first engine modified at Airworx, with the data package being completed and the dyno testing done we can now begin the endeavor of getting the STC approval. Our engineer has come up with the cost and the plan. We will potentially need someone that is will to pay for an overhaul with the modification and that will allow engineering witness flight testing. The closer to SC the better and it may take a while to get it all done. My suggestion is to contact David@airworxaviation.com as he is compiling a list of interested parties in this modification.”
John Klaerner
51’ C-170-A N1292D
KCVB
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ghostflyer
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Re: Airworx 180HP O-300 STC

Post by ghostflyer »

many years ago we fitted a “kit” from continental to increase the power output to our O-300 engine . there wasn’t any approval issued and was “going” to be a experimental . The cylinders were ported and polished and the pistons I think were C85 types. the carburettor jetting was made richer [ a new carb was fitted in the end due to the venturi had to be modified. ] and a new cam shalf fitted . When on the dyno the engine was fitted with a “club” type propellor [fixed pitch and wooden]. When on the dyno the engine had a hood fitted to catch the air coming off the propellor for cooling . The engine was run in this configuration [on the dyno] for about 8 hours before fitting into my aircraft. The engine was dynamically balanced . I do not know [cant remember] how this was done . Engine out put was “similar” to the GO-300 engine .
What a rocket ,I loved the performance but oil temperature was an issue big time . In the end we fitted a remote oil filter with cooling fins attached to the filter just to stay out of the red. I was running a standard 56 in pitch prop. I can’t remember the timing set or fuel flows ,this was over 20 years ago. The performance was similar to the Bird dog .
While sitting on the ramp one night ,the aircraft was sabotaged and the engine disintegrated on take off . Some minor damage to aircraft but engine was “toast”. The perpetrator was caught due to his boasting about it about what he had done, but unfortunately about a week later, he had a stroke, and the police could do nothing from there on.He died about 3 months later. I have lost all the paper work regarding this engine modification due to floods in my area.
Over the years I have had a number of continental engines and always been looking for improvement in performance but reliability and cost is the factor.
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Fishsticks
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Re: Airworx 180HP O-300 STC

Post by Fishsticks »

For those of you not following along on Facebook...
Continental O-300 HP upgrade STC update. We are still working on the STC and our engineer doesn’t think it is going to be an issue to get done. We are cutting our PO today so he can get it done. He has already developed the paperwork package and approved a serialized major alteration to one engine. He has also said that he will do more serialized alterations if customers need their engines done prior to FAA final STC approval. The cost to do the upgrade is going to be the same regardless of which approval method is done. Standard overhaul cost is 36500.00
HP upgrade approved data package 5000.00
Engine modifications required 5000.00
Total 46500.00
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n2582d
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Re: Airworx 180HP O-300 STC

Post by n2582d »

In that FB thread they said that it will require a propeller repitch rather than a new fixed pitch or constant speed propeller. Probably not enough demand to go through the STC process, but it seems this would be an ideal candidate for an MT-Propeller MTV-20-D electrically-governed propeller. Maybe John Nielsen could comment on how many propellers they need to sell to make it worth their time to pursue such an STC and what the price point would be for the prop, spinner, and governor combination. Over ten years ago, according to this thread, MT-Propeller said it would take ten propeller orders and would cost $10,000. Most engine upgrade STCs specify what props are required to be used with the new engine. Would be nice if Airworx would collaborate with MT-Propellers to add one of their props to the Airworx STC. Also would be nice for MT-Propeller to add a version of the MTV-20 for the 8-bolt crankshaft used on the C-145, O-300A and O-300B. The MTV-20-D is for the ARP 502 Type I flange used on the O-300C and O-300D.

The other thing Airworx said in that thread was that an oil cooler would not be required. Seems to me adding an oil cooler like Steve’s Aircraft oil cooler would be —if not a necessity — a good idea. The cooler and the STC cost roughly $1000.
Gary
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JohnNielsen
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Re: Airworx 180HP O-300 STC

Post by JohnNielsen »

MT can and has made 8 hole fixed pitch props. However, at this time, being so far backlogged with constant speed prop orders, they have placed a hard pause on all fixed pitch prop production. Price was 2850 plus frt and lead time was about 8 weeks when they were making them. Only 16 lbs. You need to provide your own spinner. I used a skull cap one. They are wood/epoxy core with a fiberglass jacket and a stainless steel leading edge.

The MT prop does NOT require an STC because most of our planes were approved with CAR 3 and our TCDS in the prop area says: "...or any wood propeller with diameter between..." The TCDS of the MT prop states it is a 'wood' propeller, thus satisfying the requirements of the C170 TCDS.

John
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n2582d
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Re: Airworx 180HP O-300 STC

Post by n2582d »

John,
Thanks for your reply. It appears that the fixed pitch MT prop does not require an STC, but that one of their MTV props (“V” denotes that it is a variable pitch prop) would require an STC to be legal on the C-170. TCDS A-799 for the C-170, under “Specifications pertinent to all models,” states, “ Sensenich 73BR-50 or any other fixed pitch wood” (propeller).

Is there enough of a market for MT to develop an STC for using one of their electric constant speed props on the C-145/O-300 powered C-170 series like Flight Resources did with STC SA02245CH? Could the same MTV prop be used on an unmodified C-145/O-300 engine and one producing 170 hp like Airworx is working on? If so, would you have a ball park figure on what the prop/spinner/controller/STC would cost?

Seems to me that it would be in Airworx best interest to work with MT-Propellers to include one of their electrically-controlled MTV props much like Stoots has done with STC SA02282AK.

On an unrelated subject, I see that SA02245CH requires the plane to be on floats. How are you able to work around this?
Last edited by n2582d on Mon Nov 27, 2023 1:20 pm, edited 1 time in total.
Gary
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Fishsticks
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Re: Airworx 180HP O-300 STC

Post by Fishsticks »

Its cool to know that you can get a fixed pitch MT prop that will work on the O-300. But if you follow the TCDS won't you be limited in diameter to 74" ?
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JohnNielsen
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Re: Airworx 180HP O-300 STC

Post by JohnNielsen »

Two answer from questions above:
1: The MT constant speed propeller STC is valid for ANY version of a -360 or -390 as long as it has hollow crankshaft and ability to mount a hydraulic governor. The 2-blade version is now priced at $16,500 plus options and frt. Two 2-blade and One 3-blade prop models are approved. There is NO restrictions to RPM or use on floats or skis with that STC.

2: The electric MT constant speed prop STC used for the 172 planes with solid crankshaft is just under $20K all in delivered in 2024. Not enough demand to support a $100K STC development investment for the O-300/C145 market. But we can do one at at time with a Field Approval done by our in-house DER for an added fee.

3: The MT fixed pitch props are limited to a max diameter of 76" by MT.

Hope that answers your questions.

John
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n2582d
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Re: Airworx 180HP O-300 STC

Post by n2582d »

I was misreading this limitation as a restriction that the MT prop could only be used on C-170s with PK 2300 series floats — i.e. wheels, skis, or floats other than PK 2300 series floats are not compatible with the MT prop.
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Gary
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rschreiber
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Re: Airworx 180HP O-300 STC

Post by rschreiber »

I just sent an email to Airworx regarding the O-300 modification. Apparently they will not be pursuing an STC, but will modify the engine under a 337. Here’s the information I received:

Just for the sake of information: we will not be pushing forward with an STC package. HOWEVER! We do have authorization to modify each engine individually. At the end of your overhaul, you would be getting a certified engine with a 337 for major alteration. I've seen a few things floating around the internet, but the paperwork is written to be 170 hp, at 8.5:1 compression ratio and a slight increase to the jetting on the carb. If you have any questions feel free to reach out.
Ryan
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GAHorn
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Re: Airworx 180HP O-300 STC

Post by GAHorn »

n2582d wrote: Tue Nov 28, 2023 9:30 pm I was misreading this limitation as a restriction that the MT prop could only be used on C-170s with PK 2300 series floats — i.e. wheels, skis, or floats other than PK 2300 series floats are not compatible with the MT prop.IMG_0589.jpeg
I can see where the prop is approved with PK2300 floats…. but I don’t see how that translates to the MT prop being “incompatible” with other wheels, skis, or floats….. only that it’s not approved for those others….(yet.)
'53 B-model N146YS SN:25713
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n2582d
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Re: Airworx 180HP O-300 STC

Post by n2582d »

I agree George, I should have used the words “not approved” or “not authorized” rather than “not compatible”. But, if I understand John correctly, this clause in the STC is saying that if the C-170 with this prop is on floats, the only floats approved are PK 2300 series floats; there is not approval to use an MT prop with any other type of floats. Seems like this could have been written more clearly in the STC because it can be easily interpreted to mean than their prop is not approved for use on a C-170 using wheels or skis.
Gary
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