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  #1  
Old 07-23-2021, 07:04 PM
Champ's Avatar
Champ Champ is offline
 
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Location: Kingsville, Ontario, Canada
Posts: 358
Default MT vs Hartzell Flight Differences

I plan on replacing my Hartzell HC-C2YR-1BFP/F7497-2 (Blended Airfoil for short) with an MTV-9-B/183-50a (3 blade) next weekend and was wondering what flight differences to expect.

1. Will it need quicker and more right rudder on take off?
2. Will it slow down quicker with throttle reduction?
3. If I get slow in the flair will my RV-8 sink more and need more throttle to keep it from bouncing?
4. The MT is about 5 lb lighter than the Hartzell, probably with less inertia. Will start up be any different?
5. Any other flight characteristics that might change? Especially thinks to look out for on first flight.
6. I have 232 hrs tach time/293 Hobbs on the Hartzell. The alternator belt looks good but would it be a good idea to replace it while the prop is off? I have a new belt just in case.
7. I'm not aerobatic or formation current yet but wonder how the MT might change these.

Here's the MT. It will probably look better on the plane:
Click image for larger version

Name:	MT.jpg
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ID:	13933



I expect better take off and climb performance but loss of a few knots in cruise. Time will tell.
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Bellanca Champ 7ACA since 1986, restored 1990.
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2021 Donation In

Last edited by Champ : 08-03-2021 at 06:14 AM. Reason: 7. Added
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  #2  
Old 07-23-2021, 09:17 PM
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rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Default

Let us know what you see for performance gain/loss.
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  #3  
Old 07-24-2021, 02:53 AM
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Quote:
Originally Posted by Champ View Post
...
I expect better take off and climb performance but loss of a few knots in cruise. Time will tell.
There were some tests run a few years ago and this is what seemed to be the consensus. I don't recall if the two props tested were these exact models, or if those props have changed over the years.

One thing to take into account is that you might need some adjustment on the prop controller or the prop fine pitch stop. Carefully check the MT manuals to see how to do this if you have not done it before. I'd also be prepared for a prop overspeed during your first takeoff, since ground running is not an exact simulation of flight for the prop, obviously.

Also, be ready for a more challenging time removing and replacing the cowl - perhaps lots of painter's tape and a helper the first few times.

Not sure where you hangar, but take care about hangar rash on the prop - one of my hangar mates has a similar prop, and it got nicked by the towbar - a chip came off of the thin trailing edge. You might consider some of those rubbery prop covers. Thankfully the repairs on the MT are not that difficult as documented in the manual - I've never done one myself, but looks "easy".
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  #4  
Old 07-24-2021, 09:16 AM
Ralph Inkster Ralph Inkster is offline
 
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Boring reminder - Hope you remember to call TC with updated equipment listing & W&B report as it affects your CofA.

Looking forward to a report on performance changes & how the 5 pounds off the nose affects your solo CofG feel & handling characteristics.
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  #5  
Old 07-24-2021, 11:42 AM
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Ralph - Thanks for the TC reminder. My RV is nose heavy solo even with the battery in the back. I keep my tool and tie down kits (18lbs) on the baggage shelf to help the CG. 5 lbs off the nose should be nice.

I did a couple of speed runs on the Hartzell to give me something to compare the MT to: 7500 ft, WOT, 23.1"MP, 2400 RPM, 77% Pwr, 15.5 GPH, Full Rich, 7deg OAT and got 173-175 knots.

I'll report on the MT performance.
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  #6  
Old 07-24-2021, 03:39 PM
g zero g zero is offline
 
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Default MT

Almost every MT prop ends up back to them for some sort of repairs…… big box and big bucks to ship a 3 blade prop .
I’d go for a 2 blade Whirlwind if you are looking at saving weight.
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  #7  
Old 07-24-2021, 04:31 PM
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Toobuilder Toobuilder is offline
 
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Flew a back to back with my Rocket and a buddy's F-1 looking for this exact comparison. My 2 blade BA made more thrust at 2700 than his 3 blade MT. At approximately the same weight, I accelerated faster, had better climb, and could almost stay with him at top speed using 2700 (which is saying something, because his airplane is FAST). But at 2300 cruise, he handily walked away.

Keep in mind this is an 80 inch Rocket specific BA Hartzel, so may not be the same as the smaller 4 banger version you have.
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  #8  
Old 07-24-2021, 05:02 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
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Quote:
Originally Posted by Champ View Post
I plan on replacing my Hartzell HC-C2YR-1BFP/F7497-2 (Blended Airfoil for short) with an MT-9-B/183-50a (3 blade) next weekend and was wondering what flight differences to expect.

1. Will it need quicker and more right rudder on take off?
2. Will it slow down quicker with throttle reduction?
3. If I get slow in the flair will my RV-8 sink more and need more throttle to keep it from bouncing?
4. The MT is about 5 lb lighter than the Hartzell, probably with less inertia. Will start up be any different?
5. Any other flight characteristics that might change? Especially thinks to look out for on first flight.
6. I have 232 hrs tach time/293 Hobbs on the Hartzell. The alternator belt looks good but would it be a good idea to replace it while the prop is off? I have a new belt just in case.
7. I'm not aerobatic or formation current yet but wonder how the MT might change these.

Here's the MT. It will probably look better on the plane:
Attachment 13933



I expect better take off and climb performance but loss of a few knots in cruise. Time will tell.
Changing your prop is considered a MAJOR CHANGE.... so you will be going back into phase 1. You will be able to answer all of your above questions.
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  #9  
Old 07-24-2021, 05:44 PM
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D Weisgerber D Weisgerber is offline
 
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Quote:
Originally Posted by gasman View Post
Changing your prop is considered a MAJOR CHANGE.... so you will be going back into phase 1. You will be able to answer all of your above questions.
Th OP is in Canada, are they required to go back to phase 1?
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  #10  
Old 07-24-2021, 08:18 PM
gasman gasman is offline
 
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Quote:
Originally Posted by D Weisgerber View Post
Th OP is in Canada, are they required to go back to phase 1?
Canada!!!

I gotta start paying attention.....
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