<p>There are too many factors to be able to give you a precise plot. All the below have major impacts on propeller performance:</p>

<ul>
<li>Activity factor

<ul>
<li>A blade with a thicker chord will generate more thrust, but have less efficiency</li>
</ul></li>
<li>Airfoil selection

<ul>
<li>Prop airfoils change as a function of radius. Some airfoils are good (bad) at low Reynolds and/or low Mach, but are bad (good) at high Reynolds and/or high Mach</li>
</ul></li>
<li>Proximity to ground

<ul>
<li>If you're close to the ground, pushing air at the ground, then you have a good efficiency bump from ground effect.</li>
</ul></li>
</ul>

<p>However, <a href="https://www.apcprop.com/files/PER3_27x13E.dat" rel="nofollow noreferrer">https://www.apcprop.com/files/PER3_27x13E.dat</a> is a good first step. The change in pitch from 12" to 13" is not going to dramatically change matters, and probably has less of an effect than flying in ground effect or airfoil changes.</p>

<p>You can also compare to <a href="https://www.apcprop.com/files/PER3_26x13E.dat" rel="nofollow noreferrer">https://www.apcprop.com/files/PER3_26x13E.dat</a>, which reduces diameter by an inch, while increasing pitch by an inch. You will likely find that a theoretical APC 27x12 will be in between the two in terms of performance.</p>

<p>I hope this is helpful. Ultimately, once you get close enough to your desired theoretical performance there's no option but to try a few blades out for empirical results.</p>

CC BY-SA 4.0
2020-05-15T14:39:31.820Z
2020-05-15T14:39:31.820Z
Kenn Sebesta
<p>I'm looking to find the amount of lift produced by a 27 inch diameter, 12 inch pitch, two-blade propeller spinning facing the ground. Are there any datasheets that show the amount of lift given at any rpm?</p>

CC BY-SA 4.0
2020-05-15T03:28:42.267Z
Thrust generation also depends greatly on the propeller pitch, not just the diameter.
ifconfig
CC BY-SA 4.0
2020-05-15T03:36:29.490Z
Thank you for visiting Drones.SE! In order to get the answer you are looking for, please add a few more details about the specifications of the propellers. Information like pitch (as mentioned above), number of blades, and any other information you have on the propellers you want information for. The more information you can provide, the better the answers will be.
Jacob B
CC BY-SA 4.0
2020-05-15T03:55:36.047Z
@GabrielKusiak Just saying that an answer can specify for any pitch doesn't help. In order to get a good answer, you'll need to be asking about a specific diameter and pitch combination, or else any answer would have to spell out every possibility under the sun, which isn't desireable.
ifconfig
CC BY-SA 4.0
2020-05-15T04:28:47.037Z
@ifconfig ok I fixed it.
Gabriel Kusiak
CC BY-SA 4.0
2020-05-15T04:36:20.020Z
As I explain in this answer, https://drones.stackexchange.com/a/743/97, a pitch of 10-12 in would be rather extreme and I don't think you'd be very linkely to find such a prop. Are you sure that's what you meant?
ifconfig
CC BY-SA 4.0
2020-05-15T04:42:55.383Z
@ifconfig I've found a prop 27 inch diameter, 12 inch prop. I also edited the question
Gabriel Kusiak
CC BY-SA 4.0
2020-05-15T04:59:46.487Z
Nice work! I too have now found several listings on Amazon and Hobbyking for 27x12x2 props, but no thrust specs... This may be better achieved with a thrust stand and a motor.
ifconfig
CC BY-SA 4.0
2020-05-16T05:18:29.083Z
@ifconfig I don't know I can agree that a 12" pitch is extreme, or even uncommon. It's generally  understood that optimally efficient props for forward flight have a similar pitch as their diameter. I have a 46.5x35" which is used on full-scale self-launch gliders. Remember that for a same AOA of the blade foil, doubling the radius means doubling the pitch, so it's natural that the pitch increase with the radius.
Kenn Sebesta
CC BY-SA 4.0
2020-05-16T05:35:32.893Z
@KennSebesta I stand corrected! Didn't realize that.
ifconfig
<propellers><thrust><spec-sheet>
Datasheets for lift of a 27x12x2 inch propeller?
Gabriel Kusiak
# Datasheets for lift of a 27x12x2 inch propeller?

(Asked by: username_0 on 2020-05-15)

I'm looking to find the amount of lift produced by a 27 inch diameter, 12 inch pitch, two-blade propeller spinning facing the ground. Are there any datasheets that show the amount of lift given at any rpm?

**Tags:** propellers, thrust, spec-sheet
> **Comments:**
> **username_1**: Thrust generation also depends greatly on the propeller pitch, not just the diameter.  
> **username_2**: Thank you for visiting Drones.SE! In order to get the answer you are looking for, please add a few more details about the specifications of the propellers. Information like pitch (as mentioned above), number of blades, and any other information you have on the propellers you want information for. The more information you can provide, the better the answers will be.  
> **username_1**: @GabrielKusiak Just saying that an answer can specify for any pitch doesn't help. In order to get a good answer, you'll need to be asking about a specific diameter and pitch combination, or else any answer would have to spell out every possibility under the sun, which isn't desireable.  
> **username_0**: @ifconfig ok I fixed it.  
> **username_1**: As I explain in this answer, https://drones.stackexchange.com/a/743/97, a pitch of 10-12 in would be rather extreme and I don't think you'd be very linkely to find such a prop. Are you sure that's what you meant?  
> **username_0**: @ifconfig I've found a prop 27 inch diameter, 12 inch prop. I also edited the question  
> **username_1**: Nice work! I too have now found several listings on Amazon and Hobbyking for 27x12x2 props, but no thrust specs... This may be better achieved with a thrust stand and a motor.  
> **username_3**: @ifconfig I don't know I can agree that a 12" pitch is extreme, or even uncommon. It's generally  understood that optimally efficient props for forward flight have a similar pitch as their diameter. I have a 46.5x35" which is used on full-scale self-launch gliders. Remember that for a same AOA of the blade foil, doubling the radius means doubling the pitch, so it's natural that the pitch increase with the radius.  
> **username_1**: @KennSebesta I stand corrected! Didn't realize that.  

---

## 1 answers

### Answer by username_3 on 2020-05-15. Score: 2

There are too many factors to be able to give you a precise plot. All the below have major impacts on propeller performance:

* Activity factor
  + A blade with a thicker chord will generate more thrust, but have less efficiency
* Airfoil selection
  + Prop airfoils change as a function of radius. Some airfoils are good (bad) at low Reynolds and/or low Mach, but are bad (good) at high Reynolds and/or high Mach
* Proximity to ground
  + If you're close to the ground, pushing air at the ground, then you have a good efficiency bump from ground effect.

However, <https://www.apcprop.com/files/PER3_27x13E.dat> is a good first step. The change in pitch from 12" to 13" is not going to dramatically change matters, and probably has less of an effect than flying in ground effect or airfoil changes.

You can also compare to <https://www.apcprop.com/files/PER3_26x13E.dat>, which reduces diameter by an inch, while increasing pitch by an inch. You will likely find that a theoretical APC 27x12 will be in between the two in terms of performance.

I hope this is helpful. Ultimately, once you get close enough to your desired theoretical performance there's no option but to try a few blades out for empirical results.


---

