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RC Models => Electric Planes => Topic started by: DominicM on July 17, 2024, 09:09:27 PM



Title: Tyler Perry's Giant XXXL 149KG C-17 Globemaster flies at Airliner Meeting
Post by: DominicM on July 17, 2024, 09:09:27 PM
Tyler Perry's 1st flight of Ramy RC's Giant 149KG XXL C-17 Globemaster at Airliner Meeting 2024. Tyler flies in less than ideal conditions on the first day (i.e. Friday) of the Airliner Meeting Show. There was a 15mph cross wind but that didn't stop him from getting this big quad EDF powered jet into the air.

This unique EDF jet was constructed by Ramy RC in Atlanta, United States and shipped to Oppingen, Germany just for this event. It weights 149KG and is powered by 4 200mm EDFs running on 14S. The maximum pack capacity used per EDF is 17000mah.  Wingspan is 6.4 meters (21 ft), length is 6.35 meters (20.9 ft).

https://www.youtube.com/watch?v=wWqBVa7edUQ


Title: Re: Tyler Perry's Giant XXXL 149KG C-17 Globemaster flies at Airliner Meeting
Post by: K K Iyer on July 18, 2024, 11:50:55 PM
@DominicM,

A fantastic video, as we’ve come to expect from you.

It set me a-thinking...

They way (s)he took off tells that the wing loading is low
The aspect ratio is perhaps 8 or 9
On a 21’ span, that is ~2.5’ avg chord, or say 50sqft wing area
That’s about 6-7lbs/sqft for 330lbs AUW
I’ve no idea if that’s a low wing loading for the size, but the takeoff suggests it is

Now let’s look at the power
17000mah per EDF
Assuming 9000mah consumption in a 6 minute flight, the current draw was probably 90amps
On 14s say 50volts
So about 4500w
Or say 18kw total for four (or over 20bhp!)

Now comes the interesting part
18000w for a 330lb plane is some 50-60w/lb

That’s a typical power loading for an RC Oldtimer or trainer!

The mind boggles!



Title: Re: Tyler Perry's Giant XXXL 149KG C-17 Globemaster flies at Airliner Meeting
Post by: manu on July 19, 2024, 12:54:48 AM
Why have you considered 14s as 50volts, Sir?


Title: Re: Tyler Perry's Giant XXXL 149KG C-17 Globemaster flies at Airliner Meeting
Post by: DominicM on July 20, 2024, 01:09:06 PM
Yes. Crazy low wing loading somehow. On my next video it takes literally no runway to get airborne. It's an amazing RC engineering project...and they've got bigger and better stuff planned for 2 years time.


Title: Re: Tyler Perry's Giant XXXL 149KG C-17 Globemaster flies at Airliner Meeting
Post by: K K Iyer on July 20, 2024, 11:09:36 PM
@DominicM,

Sir,
Are you on RCGroups or not?
If you are, then I won’t need to post your stuff there, in the Vintage Forum where I usually post.
Regards
Iyer


Title: Re: Tyler Perry's Giant XXXL 149KG C-17 Globemaster flies at Airliner Meeting
Post by: K K Iyer on July 20, 2024, 11:16:52 PM
Why have you considered 14s as 50volts, Sir?

Just a simplification to ease calculations without a calculator,
After all, if 3s is 12v, 15s is 60v.
So what’s the problem with taking 14s as 50v?
I did write ‘say’ 50v, didn’t I?


Title: Re: Tyler Perry's Giant XXXL 149KG C-17 Globemaster flies at Airliner Meeting
Post by: manu on July 21, 2024, 11:27:48 PM
Yeah, even if we consider it 58.8 volts, it would be 64 w/lb, not so far off from the 50-60w/lb