Van's has changed Hartzell recommendations
 

FWI. Van's has removed a number of props from there order form (but the form has the same rev #). There are now only 4 choices, one for I(O)-320's, one for I(O)-540 and two for I(O)-360's. The 180 hp and 200 hp now get the same prop the C2YR-1BFP/F7497 in either 72" or 74".

I faxed in my order yesterday for a F7496 and got a call in the afternoon explaining that Hartzell now recommends the F7497.

BTW. I printed the "old" order form on Sunday and noticed that the current form has removed the F7496's or F7666A4 as options.

Do you know what the restrictions are for this prop on an IO-360, 180 HP? It is no longer in the catalog and I can' find it on the Hartzell of Van web site.

I asked Hartzell tech support ...
 

I sent a note to Hartzell asking why the change and if there are any restrictions. I will post their reply when I get it.

There's a spreadsheet somewhere in the props/engine section from Les, the Hartzell guy. Posted a couple of months ago. The 4797 has no restrictions.

*edit - in the FAQ, http://www.vansairforce.net/faq.htm

I have had confirmation from Hartzell that their 7497 prop has
been officially approved on 180HP Lycomings with no operating
restrictions or placards. I have the e-mail at work so I can't reproduce it here but will do so tomorrow AM, unless someone else has done it by then.

The TCDS will state the following engines:
IO-360-B1A, -B1B, -B1D, -B1E, -B1F, -E1A, -M1A

This TCDS is OK for the Lyclones here in the UK, tho obviously I don't know about the US. I think this change has been coming for some time and in fact I ordered a 7497 some months ago for my Superior 180hp as Hartzell were very firm in their view that it was th prop to go for.

Hope that helps

Chris.

HA - srv got there first!

No restrictions at all?
 

chris mitchell writes: I have had confirmation from Hartzell that their 7497 prop has
been officially approved on 180HP Lycomings with no operating
restrictions or placards. I have the e-mail at work so I can't reproduce it here but will do so tomorrow AM, unless someone else has done it by then.

What about electronic ignition and 9:1 pistons?

Yep its cool
 

I had a long talk with hartzell.

The 7496 was their first go at it. Its a fine blade and a little thinner than the 7497. As they developed the 7497 for the IO360 angle valve they realized it would work on the 180HP as well with out the small limitations.

I asked about weight and loss of performance?

Yes the 7497 weighs a little more but as a precentage of the props total weight its very small (no specifics given).

Performance? Talking to the engineer that did the flight test development for the 7497 the there may be a slight hit on speed, but its too small to measure. Hartzell has the same challenges in getting good flight test data like we all do, especially when trying to compare two different props.

If you have the 7496 blade its still rocks and you do get that slight weight advantage and minor edge on speed. The limits on the 7496 are pretty minor. So if you have a 180HP 360 you have the choice of either. However if buying new today, the 7497 with no limits is the way to go as Hartzell recommends.

I don't know about 9:1 pistons but here is a clip of an e-mail from Hartzell in respnse to a question about LASAR ignition - in UK we have to use at least one magneto so we cannot have a totally electronic ignition system

"The LASAR ignition is basically an electronic ignition system that piggybacks onto a relatively standard magneto. As I understand, it provides the timing advance capability like other electronic ignitions but the backup mode is a standard magneto. Although we have not tested a true electronic ignition on the -M1( ) and cannot give an official approval, I personally feel the 7497 is the best choice for that combination. Some of the Superior and ECi engine clones do not have dampers, but I suspect the 7497 could also be approved on those engines as well. When we did testing with the 7496, we found the Superior O/IO-360-B1A2 (no dampers) was better than the Lycoming."

I cannot work out how to add the .pdf from Hartzell for the TCDS here - if someone can tell me I'll gladly add it!

Chris

I got this tech sheet from Hartzel this morning. Here is the text:




Flight testing of a new "blended airfoil" Hartzell propeller has been accomplished in accordance to FAR 23.907 to ensure compatibility with the Lycoming O-360-A1(A, C, D, F, G, H, P). As a result of this testing, Hartzell propeller model HC-(C,F,M)2YR-1(B)FP/F7497 is recommended for use with these engines. The following results were obtained:

Hartzell Propeller Model HC-(C,F,M)2YR-1(B)FP/F7497 is vibrationally approved when mounted on Lycoming Model O-360-A1(A, C, D, F, G, H, P) engines rated at 180 HP at 2700 RPM without dampers (8.5:1 compression ratio) with magneto ignition and installed in normal category type single engine tractor aircraft such as the Van's RV series. There are no operating restrictions.

Diameter range is 74" to 72".

At this time no aerobatic testing has been performed with the above listed propeller and engine combinations.

Testing of this propeller on the Lycoming Model O-360-A1( ) engine equipped with Electronic Ignition and/or FADEC has not been conducted at this time.

Hartzell Propeller Model HC-(C,F,M)2YR-1(B)FP/F7497 is vibrationally approved when mounted on Superior Model O-360-B( )( )2engines rated at 180 HP at 2700 RPM without dampers (8.5:1 compression ratio) with magneto or electronic ignition and installed in normal category type single engine tractor aircraft such as the Van's RV series. There are no operating restrictions.

Diameter range is 74" to 72".

At this time no aerobatic testing has been performed with the above listed propeller and engine combinations.

Testing of this propeller on the Superior Model O-360-B( )( )2 engine equipped with FADEC has not been conducted and is not a recommended combination.

NOTE: Propeller vibration characteristics and stress amplitudes on a reciprocating engine installation are primarily mechanically generated by the engine. Any modification to the standard engine configuration to include high-compression pistons, electronic ignition, FADEC, tuned induction and exhaust, and turbo-charging or turbo-normalizing have the potential to adversely affect the propeller vibration characteristics and stress amplitudes. Hartzell Propeller therefore does not endorse any such engine modification unless the specific engine and propeller configurations have been tested and found to be vibrationally acceptable according to 14 CFR 23.907.

The Hartzel tech sheet, which is quoted above, lists tuned exhaust as having a potentially adverse affect on prop vibration and stress.

My sense is that most of us run tuned exhaust systems like Larry Vetterman's. I do. And, it's a great product. I see many threads addressing the potential impact of high compression pistons and electronic ignition on prop vibration and stress. But, I don't see much about tuned exhaust. Why?

Is the conventional wisdom that tuned exhaust has only a negligible impact on prop vibration and stress? I'm just lookin' to learn something. :)