Rafi Nahmani
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Rafi Nahmani's Discussions

How to get my drone to fly for 3 to 5 hours??

Started this discussion. Last reply by Rafi Nahmani May 6. 3 Replies

I have seen hydrogen fuel cells power drones for 3 to 5 hours but most fuel cells on the market that i have seen are really overpriced! I have also heard of goodenoughs new glass electrolyte battery…Continue

Ducted fan motors vs propellers??

Started this discussion. Last reply by Sam Worthington Feb 3. 6 Replies

Ducted fan UAVs maintain a higher payload to stored volume ratio. The vehicle can carry 4x the payload of a similar footprint fixed- or open-rotor UAV. I have heard different things online about…Continue

How to get Griff 300 specs??

Started this discussion. Last reply by Josip Nunth Mar 31. 2 Replies

"The Griff 300 gets its name from the number of kilos it can lift and carry. Converted to U.S. measurements, the drone can lift up to 660 pounds, including the drone's own 1…Continue

How to get longest flight time on octocopter that has decent payload already on it?

Started this discussion. Last reply by RM Aviation Aug 28, 2017. 15 Replies

I want to design an octocopter that will respond to incidences of crime and terrorist attacks. Survey and gather intel and come back to HQI want this Octocopter to carry radioactive/chemical testing…Continue

 

Rafi Nahmani's Page

Latest Activity

Hans H. replied to Rafi Nahmani's discussion In Search of an Advanced Drone Build!
"You dont have a BEC. You dont have a charger for the battery. You dont have a GPS. You ... like to have more then 1 battery. You need a data link on 433MHz to get telemetry. You need a laptop (and sunshade) to do map / telemetry / config in the…"
Jul 21
Jean Lee replied to Rafi Nahmani's discussion In Search of an Advanced Drone Build!
"Personally, I really like to build from the most basic parts available, getting to make more complex parts yourself. It's more difficult and time-consuming, but also feels a lot more rewarding and saves more time. I bought most of the cheap…"
Jul 19
Rafi Nahmani replied to Rafi Nahmani's discussion How to get my drone to fly for 3 to 5 hours??
"Thanks for the reply. Very informative. I've actually been looking into turbine engines. Seen this one   https://jakadofsky.com/index1.php?lang=en&bereichID=11 ; Have you seen any others mind??"
May 6
Ian CL replied to Rafi Nahmani's discussion How to get my drone to fly for 3 to 5 hours??
"Yes, I think "nobody" replied because there is no energy source which provides 3x the energy density of batteries which are suitable for small aircraft.Beyond all the "promising" battery technologies (lithium air, sodium) which…"
May 6
Josip Nunth replied to Rafi Nahmani's discussion How to get Griff 300 specs??
Mar 31
Josip Nunth replied to Rafi Nahmani's discussion How to get Griff 300 specs??
"The specifications of this company are not true, someone has forgot to make some calculations!!! GRIFF 350: Dimensions: 265cm x 280cm x 50cm Dimensions folded: 90cm wide x 160cm Rated payload: 150Kg (45 min) Maxumum payload: 200kg MTOW : 350kg The…"
Mar 31
Rafi Nahmani replied to Rafi Nahmani's discussion How to get my drone to fly for 3 to 5 hours??
"Nobody?"
Mar 3
Rafi Nahmani posted a discussion

How to get my drone to fly for 3 to 5 hours??

I have seen hydrogen fuel cells power drones for 3 to 5 hours but most fuel cells on the market that i have seen are really overpriced! I have also heard of goodenoughs new glass electrolyte battery coming out in a few years its suppose to have incredible specs.Hybrid electric gas / battery powered drones also get great flight times down side is they are really loud and cause a lot of vibrationsWhen this stuff becomes mainstream its going to change the drone industry!Are there any other forms…See More
Mar 2
Sam Worthington replied to Rafi Nahmani's discussion Ducted fan motors vs propellers??
"Rafi, I'm not sure about the 2x or 4x efficiency claims, but you could expect a 30% or 40% increase in static thrust for a well designed ducted fan compared to an open propellor of an equivalent diameter. I'll keep meaning to work through…"
Feb 3
Rafi Nahmani replied to Rafi Nahmani's discussion Ducted fan motors vs propellers??
"First and second article are really convincing"
Jan 29
Rafi Nahmani replied to Rafi Nahmani's discussion Ducted fan motors vs propellers??
"http://www.avidaerospace.com/blog/2015/3/24/the-case-for-ducted-fan-uavs ??? By reducing propeller blade tip losses, the ducted fan is more efficient in producing thrust than a conventional propeller of similar diameter,…"
Jan 29

Moderator
Graham Dyer replied to Rafi Nahmani's discussion Ducted fan motors vs propellers??
Jan 29
Andre K. replied to Rafi Nahmani's discussion Ducted fan motors vs propellers??
"Ducted fan is less efficient, and much less efficient if you need horizontal speed too, not only hover."
Jan 29

Moderator
Graham Dyer replied to Rafi Nahmani's discussion Ducted fan motors vs propellers??
"Ducted fans are less efficient, because a smaller mass of air is used for propulsion and additional friction drag and added weight from the shroud and support structure. The highest propulsion efficiency is a large, slow-spinning prop, not a small…"
Jan 28
Rafi Nahmani posted discussions
Jan 28

Profile Information

About Me:
Passion for technology. Full time chemist,part time entrepreneur.
Please tell us a bit about your UAV interest
Seeking to develope a nearly impossible concept of drone.
Hometown:
Los angeles

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