[Mike F]

I'm getting ready to purchase the engine and prop for my RV-7 and I came across what appears to be misleading info on Vans order form for a Hartzell BA prop.

I'm looking hard at the XIO-360-M1B 180 HP engine and a Hartzell blended airfoil prop. The order form suggests/recommends the 72" and 74" C2YR-1BF/F7496 for (I)O-360 180 HP engines. I was concerned about RPM limitations so I contacted Hartzell technical support for more specific information. On one of the charts they sent me, the combo recommended by Vans (above), is marked "combination not recommended" when the IO-360-M1B has Lasar.

I asked for more clarification and was told by Hartzell that they are wrapping up some new testing and will soon be recommending the 72" and 74" C2YR-1BFP/F7497 BA for the XIO-360-M1B engine with standard mags (it's already approved with LASAR). In addition, there are no RPM restrictions with this combo. Vans order form recommends this prop for 200 HP engines only. More conflicting information but there is no doubt that Hartzell is the authority in this matter.

So it appears I almost ordered the wrong prop based on a bad order form. I'm posting this info as a heads up for other RV'ers that are about to do the same thing. There's also a chance that I'm wrong with my analysis so I'm open to any corrections or comments.

 

[gmcjetpilot]

Thanks for the help, good info

Yep there was some good threads on this, but that is a good point. Here is a helpful table and threads:

(note the 7497 is listed for the 180 hp engine as well as 200 hp, with out the placard. The 1870 HP O-360-A1A I gather is like a 180 HP (X)IO-360-M1B, with FI. Not sure about the "X" you have on there, but you are right the 7497 looks like the better choice for both 180/200HP engines.)




Optimal Hartzell for modified engines?

Hartzell prop advice? (diameter)

Older Hartzell or newer blended airfoil?

 

[osxuser]

Yep there was some good threads on this, but that is a good point. Here is a helpful table and threads:

(note the 7497 is listed for the 180 hp engine as well as 200 hp, with out the placard. The 1870 HP O-360-A1A I gather is like a 180 HP (X)IO-360-M1B, with FI. Not sure about the "X" you have on there, but you are right the 7497 looks like the better choice for both 180/200HP engines.)




Optimal Hartzell for modified engines?

Hartzell prop advice? (diameter)

Older Hartzell or newer blended airfoil?

The IO-360M1B is horizontal Induction, as opposed to vertical on the O-360A1A (Besides the Obvious Fuel Injection). I don't think that the 7496 is worth buying in ANY case since it doesn't work with the IO-360 Angle valves, and the 7497 works with ALL of them. That way if you change engines you don't have to change props. I do believe the 7497 is a touch heavier though.

 

[Davepar]

Note that the M1B in that chart had a Powerflow exhaust. I would think that had more to do with the power output than M1B vs. all the 180hp engines which were approved for the F7496. Still, I agree the F7497 looks like a better choice these days.

 

[srv]

7496 vs. 7497

All the m1b owners (and one tech counseler), I've talked to are using the 7496 and happy. In my correspondence with Hartzell, you're OK if you can live with the placard limitations and you're not using powerflow.

I never found any m1b owners using the 7497, but that is what they recommend now, it's tested on the Diamonds with no limitations (even if using powerflow), and as noted above, could be used on an angle-valve. So that's what I ordered this month.

Les said they were going to be updating Van's on these recommendations, but given the Hartzell site listings don't even list a 7496, it'll probably be awhile.

 

[Davepar]

The F7497 is new, so that's probably why you're not seeing it around as much as the F7496.

 

[dan]

The place to look is not necessarily "web sites." Look at the TCDSs (type certificate data sheets).

http://tinyurl.com/22angt

This won't paste all that well, but...

            Maximum            Diameter Approx. Max. Wt. Complete Blade
Blades     Continuous Takeoff   Limits (For Reference Only) Construction
(see Note 2) HP RPM HP RPM (see Note 2) (see Notes 3 and 7) (See Note 10)

7497-0 250 2700 250 2700 74? to 68? 51.8 lb. Aluminum Alloy

...and in terms of engine approval/placards:

HC-C2YR-
1BFP
F7497 LYC O-360-A1A, -A1C, -A1D, -A1F,
-A1G, -A1H, -A1P
74 72 none

HC-C2YR-
1BFP
F7497 LYC IO-360-A1A, -A1B, -A1C,
-A1D, -C1A, -C1B, -C1C, -C1F,
-D1A
74 72 Continuous operation is
prohibited above 24 inches
manifold pressure between
2350 and 2550 RPM

HC-C2YR-
1BFP
F7497 LYC IO-360-A1B6, -A1B6D, -A1D6,
-A1D6D, -C1C6, -C1D6, -C1E6,
-C1E6D
74 72 none

 

[7pilot]

72 or 74 what is the difference?

Can anyone tell me what the difference is? (Other than 2 inches? )

 

[osxuser]

It's been discussed before (do a search) but the general agreement is, 1 inch more ground clearance, but no reduction in diameter allowed with the 72". Most people opt for the 74", as I would.