Vno and Vne

[Tomwr]

I am trying to find out which criteria these speedes are based on in terms of gustfactors, relationship to other speeds, flutter, over-g, weights etc. Does anyone know?

 

[Avanza]

In aviation, V-speeds are standard terms used to define air speeds important or useful to the operation of all aircraft.
[1] These speeds are derived from data obtained by aircraft designers and manufacturers during flight testing for aircraft type-certification.

Ref: 1 Love, Michael C. (2005). "2". Better Takeoffs & Landings. Mc-Graw Hill. pp. 13–15. ISBN 0-07-038805-9. Retrieved 7 May 2008.

V speeds - Wikipedia

en.wikipedia.org

Good luck

 

[Tomwr]

Hi Avanza, thanks for your reply. My question is somewhat more in depth. I am asking how the actual numbers are determined/calculated - i.e. for an RV-7. According to the RV-7 POH, Vne is 200 kts IAS and Vno 167 kts IAS. How are these numbers calculated? I have read somewhere that when flying at Vno, the aircraft must withstand a gust load of 50 fps - i guess without esperience any structural deformations. Ref my initial question about g-loads, weights etc.

 

[rstory]

Hi Avanza, thanks for your reply. My question is somewhat more in depth. I am asking how the actual numbers are determined/calculated - i.e. for an RV-7. According to the RV-7 POH, Vne is 200 kts IAS and Vno 167 kts IAS. How are these numbers calculated? I have read somewhere that when flying at Vno, the aircraft must withstand a gust load of 50 fps - i guess without esperience any structural deformations. Ref my initial question about g-loads, weights etc.

FAR Part 23 was rewritten a few years ago, but you can read the content of Part 23 before the rewrite (it was very prescriptive before) and it contains the information on how certain airspeeds should be determined for certification.

The site I found with the Part 23 content can be found by clicking here and you want to look at Section 23.1505.

 

[Tomwr]

FAR Part 23 was rewritten a few years ago, but you can read the content of Part 23 before the rewrite (it was very prescriptive before) and it contains the information on how certain airspeeds should be determined for certification.

The site I found with the Part 23 content can be found by clicking here and you want to look at Section 23.1505.

Thanks, I,ll look into that.

 

[David Paule]

Also look up V-n diagrams.

Dave

 

[rocketman1988]

Hi Avanza, thanks for your reply. My question is somewhat more in depth. I am asking how the actual numbers are determined/calculated - i.e. for an RV-7. According to the RV-7 POH, Vne is 200 kts IAS and Vno 167 kts IAS. How are these numbers calculated? I have read somewhere that when flying at Vno, the aircraft must withstand a gust load of 50 fps - i guess without esperience any structural deformations. Ref my initial question about g-loads, weights etc.

I think the answer to your question is beyond the scope of this forum. There are some good places to start, though. I like the “Aircraft Design” series of books by Lan & Roskam.

 

[RV8JD]

Hi Avanza, thanks for your reply. My question is somewhat more in depth. I am asking how the actual numbers are determined/calculated - i.e. for an RV-7. According to the RV-7 POH, Vne is 200 kts IAS and Vno 167 kts IAS. How are these numbers calculated? I have read somewhere that when flying at Vno, the aircraft must withstand a gust load of 50 fps - i guess without esperience any structural deformations. Ref my initial question about g-loads, weights etc.

Note that Van's has changed the Vne definition from 200 KIAS/230 MPH IAS to 200 KTAS/230 MPH TAS, specifically to improve the airplane's flutter margins at higher altitudes. Unfortunately they never issued an SB or SL with this critical safety-of-flight information change, but they did update Section 15 of the builder's manual: https://www.vansaircraft.com/service-information-and-revisions/manual-section-15/

​

Also, note that Van's Aircraft never issued a POH for the RV-7 since every RV-7 is different. And be skeptical of any POH you get off the internet, as many contain either errors or information specific to the builder's airplane.​

 

[Tomwr]

Note that Van's has changed the Vne definition from 200 KIAS/230 MPH IAS to 200 KTAS/230 MPH TAS, specifically to improve the airplane's flutter margins at higher altitudes. Unfortunately they never issued an SB or SL with this critical safety-of-flight information change, but they did update Section 15 of the builder's manual: https://www.vansaircraft.com/service-information-and-revisions/manual-section-15/

View attachment 61689​

​

Also, note that Van's Aircraft never issued a POH for the RV-7 since every RV-7 is different. And be skeptical of any POH you get off the internet, as many contain either errors or information specific to the builder's airplane.​

Hi RV8JD,
Good heads up. Thank you for the response.

 

[Tomwr]

I think the answer to your question is beyond the scope of this forum. There are some good places to start, though. I like the “Aircraft Design” series of books by Lan & Roskam.

Hi rocketman1988,
Thanks.