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Archive for June, 2015
Posted by PeterVRC | Jun 23, 2015 @ 10:28 AM | 16,763 Views
Yet another FlyFly kit....
I decided to make up a 70mm EDF version of the FlyFly Mirage2000 90mm jet. Apparently a lot of the FlyFly jets fly very well on 70mm EDF combos, but only "light" versions, typically a hand/bungee launch... no landing gear etc. That is because you typically get 1300W to 1500W from a powerful 70mm EDF combo - not 2000W to 3000W of a 90mm combo!

To make it more flexible, I am actually making it up as a 90mm and THEN change down the fan to 70mm. The reason for that is so that it is all setup for any future 90mm use, and adding retracts etc, but I will fly it as the 70mmm first.

I have a Jetfan/HET 1500kv combo that does almost 1800Watts on 7S. This is enough for the hand/bungee version setup, and I would expect all the extra weight of that fan and its batteries would pretty much end up the same as running a 1300W 70mm fan with its smaller/lighter batteries. So it will be interesting to see BOTH cases!!

Seeing it is being done as a very basic build, it should be VERY quick!
In one night I did all the wing and fuselage assembly, including modding the hatch/battery area to have a tray that can also fit two 4S 5000mAH in-line... allowing setups of 6S, 7S, 8S. But the main aim is the 7S for 90mm and 6S for 70mm.

It will be Fiber-glassed with WBPU, and painted up 'nicely'.... and hopefully will be a fair way under 2.5Kg for the 70mm AUW (2.2Kg?), and maybe a bit over 2.5Kg for the 90mm 7S AUW.

Posted by PeterVRC | Jun 12, 2015 @ 09:04 AM | 16,283 Views
It seems like time for another jet..... hmmm, too many unfinished really!!!!

The FlyFly Twin 90mm Mig-29
Whilst "Twin 90mm" makes it sound BIG, it is really much the same size as any twin 70mm version.

One good thing is that seeing a full scale Mig-29 is not a large jet (similar to a F-16), it means this is a 'bigger scale number' than many others. Thus it is an aircraft of considerable 'bulk'. ie It is 1/10th scale
The Twin 90mm construction also means the ducting etc is large.... so no restrictions to airflow for fans - which you can actually use 70mm's, 80mm's, or 90mm's... and ALL will fly totally fine and great! But it is easier to get high... 'huge'... power from a pair of 80mm or 90mm fans. So if you want over 1:1 Thrust to Weight then 80mm or 90mm is best. If you just want a FAST jet... 70mm's will do fine!
I have still not decided what I will sue for sure, but 90mm is leading the way because you can use two LOW/Med power fans to still get a huge result, and 90mm fans are more efficient than smaller diameters.

I also had to decide over what to DO with it in total.... and I decided to once again go "Full House" with Retracts, Flaps, Ailerons, Rudders, All Moving Stabs. Seeing it can reasonably easily get well over 4Kg thrust anyway. Unlike the Su-35 Twin 70mm which struggles to get near 1:1 !