Props - how much is too much for the motor?

[Geronimo]

I'm brand new to electric motors, and I have the FT C Pack with 10 x 4.5 props. I'm looking for a more durable prop, but the smallest APC prop at the local shop is 10x6 or 9x6. I see online APC makes a 10x5E and 9x4.5E

Is there some resource for matching props to motors? The prop the motor came with is my only clue.

 

[FL_Engineer]

I'm still searching for a good durable prob myself but I've have lots of recommendations for switching to the same prop size but getting the sport version instead of the thin electric or "E". Most people love APC, some swear by Master Air Screw, GEMFAN seem to be bottom of the barrel but will work in a pinch (just plan on replacing often).

 

[Namactual]

A 9x6E will work with the C-Pack motor. In fact, that used to ship with the C-Pack a while back. It will have a little less static thrust than the 10x4.5 but will have a higher top speed potential if the airframe allows. It will draw about the same amps as well.

There really is no definitive guide for props and motors because there are so many variables. Learning through asking questions and trial and error is about the best you can do.

Ideally, you would want to pick a watt meter. That way you could “bench” test your motor/prop combo before putting it in the air.

You can do some shade tree testing if you do not have one simply by running the combo at WOT for a few and feeling the motor and ESC afterwords. If it is too hot to touch, you are probably drawing too many amps. Just remember that ESC with built in BEC’s will get hot on their own, even without the motor draw.

 

[Geronimo]

A 9x6E will work with the C-Pack motor. ~SNIP~
You can do some shade tree testing if you do not have one simply by running the combo at WOT for a few and feeling the motor and ESC afterwords. If it is too hot to touch, you are probably drawing too many amps. Just remember that ESC with built in BEC’s will get hot on their own, even without the motor draw.

Very interesting!

 

[FDS]

The non slow fly type APC props, the grey ones with an elbow shape to the blade are more durable. They have more meat at the hub, which makes them a bit tougher. If you are breaking props landing then you need to change your technique or make some undercarriag.

 

[BATTLEAXE]

For the C pack motor the usual go to for me has been the APC 9x6 Sport props, especially for learning. They take hits the best out of all props. They are meant for glow engines But work the same on electric. They are marginally less efficient on power but not enough to really notice and will fly just about all the planes in the FT arsenal. From there you can adjust for larger planes or different flying styles using the same motor just by changing the size or pitch of the props

 

[Figure9]

The non slow fly type APC props, the grey ones with an elbow shape to the blade are more durable. They have more meat at the hub, which makes them a bit tougher. If you are breaking props landing then you need to change your technique or make some undercarriag.

Hello @FDS How right you are! I think FT should take note of this as the orders I made for a ’B’ Power Pack resulted in broken props with every landing (Even the rare good landings.) with my Bloody Baron 1st build. Landing gear fixed the problem but had a detrimental effect on the flight envelope performance & required a higher flying skillset. Ordering more durable props like the props you recommend & setting up a switch for ‘Prop Inhibit’ ended up being the best fix for me. Ed has a video about it on his Noob Tube & advice from @BATTLEAXE provided the info I needed so the whining stopped & the tears went away.

 

[Figure9]

For the C pack motor the usual go to for me has been the APC 9x6 Sport props, especially for learning. They take hits the best out of all props. They are meant for glow engines But work the same on electric. They are marginally less efficient on power but not enough to really notice and will fly just about all the planes in the FT arsenal. From there you can adjust for larger planes or different flying styles using the same motor just by changing the size or pitch of the props

Plus 1

 

[sprzout]

FT used to ship with HQProps. While they worked, they chipped more often than not for me, and I'm not sure how - I never had props hitting the ground with them unless it was me physically setting the plane down and the prop touching the ground. Nevertheless, they'd still get chipped. Best I could figure was that I was hitting bugs in the air or something...After I switched out to APCs, the problem went away.

Several of the guys at my field like the Master Air Screw props, but I can never find them. Amazon doesn't have them in the sizes I need, and the hobby shops all have empty spots on the shelves...

 

[BATTLEAXE]

FT used to ship with HQProps. While they worked, they chipped more often than not for me, and I'm not sure how - I never had props hitting the ground with them unless it was me physically setting the plane down and the prop touching the ground. Nevertheless, they'd still get chipped. Best I could figure was that I was hitting bugs in the air or something...After I switched out to APCs, the problem went away.

Several of the guys at my field like the Master Air Screw props, but I can never find them. Amazon doesn't have them in the sizes I need, and the hobby shops all have empty spots on the shelves...

FT carries MA props in their online store. I got my last 11x7x3 there. They make solid props too

 

[sprzout]

FT carries MA props in their online store. I got my last 11x7x3 there. They make solid props too

Good to know! I'll have to look into their selections.

 

[Geronimo]

The non slow fly type APC props, the grey ones with an elbow shape to the blade are more durable. They have more meat at the hub, which makes them a bit tougher. If you are breaking props landing then you need to change your technique or make some undercarriag.

So far, it's one flight and one broken prop. The plane went down pretty flat on its belly with the engine stopped, but the prop snagged some grass and dug in. No damage to the plane. Everyone said the HQ props that ship with the power pack are about as breakable as the slow fly props.

 

[Geronimo]

FT used to ship with HQProps. While they worked, they chipped more often than not for me, and I'm not sure how - I never had props hitting the ground with them unless it was me physically setting the plane down and the prop touching the ground. Nevertheless, they'd still get chipped. Best I could figure was that I was hitting bugs in the air or something...After I switched out to APCs, the problem went away.

I've heard this same thing on several threads now. I placed an order for some 10x5E APC props. It sounds like the 9x6 sport props might be the real answer. With gas engines I actually preferred the wood MAS props, but landing on wheels means you almost never need worry about the prop.

 

[BATTLEAXE]

I've heard this same thing on several threads now. I placed an order for some 10x5E APC props. It sounds like the 9x6 sport props might be the real answer. With gas engines I actually preferred the wood MAS props, but landing on wheels means you almost never need worry about the prop.

As long as you have a feasible area to land on and you are proficient enough to land on your wheels. Myself I rarely have good areas to land on with wheels, and my landing expertise is 50/50. HQ props are the weakest props I have had on the plane, any belly landing will break them. Go to APC Sport props and you will smile more after a flight, or five flights, or ten flights. If you are used to breaking props with HQ, then your mind will be blown with APC... just sayin

 

[Namactual]

I usually stick to APC E's and Sports for the C-Pack planes as well. I never really cared for the SF. I have used a few MAS plastics, but they did not seem to bite as well as the APC's with the same specs. They are great props, but tend to have less thrust and pull less amps.

That has been my experience anyway.

 

[Figure9]

FT used to ship with HQProps. While they worked, they chipped more often than not for me, and I'm not sure how - I never had props hitting the ground with them unless it was me physically setting the plane down and the prop touching the ground. Nevertheless, they'd still get chipped. Best I could figure was that I was hitting bugs in the air or something...After I switched out to APCs, the problem went away.

Several of the guys at my field like the Master Air Screw props, but I can never find them. Amazon doesn't have them in the sizes I need, and the hobby shops all have empty spots on the shelves...

You might not be hitting anything. Linear tip speed might be enough to do tip damage even in flight due to invisible mini stress line factors. I worked on full scales all my life & noted taxi damage to props that never contacted the ground. This was due to a mini low press area directly below the bottom arc of the prop, between the prop tips & the ground. Frequently you might even see a mini dust-devil, it was clear to me that the tip speeds drew tiny particles up into that lower arc & caused tip damage. That damage I ended up repairing on 25, 50, 100 hr & annual inspections.
FYI, if you love your propellers, don’t fly Cessna Skymasters.

 

[quorneng]

It is perhaps worth mentioning that if a prop is too strong something else is more likely to break or maybe worse bend the motor shaft.
With a belly landing you have to choose what bit is to be put at risk.

 

[FDS]

I found the firewall was the next thing to break....

 

[The Hangar]

I've heard this same thing on several threads now. I placed an order for some 10x5E APC props. It sounds like the 9x6 sport props might be the real answer. With gas engines I actually preferred the wood MAS props, but landing on wheels means you almost never need worry about the prop.

The 10x5E props are my go to for the C and B pack these days! They are super tough and take a lot of abuse but have great thrust as well! Good choice!