This my first EDF plane. I have flown nitro ducted fan and many go fast planes. Haven't flown mant electrics so I am really lost on this one.

The plane is a Kress/Ziroli Saab Viggen which calls out for a Kress RK 709E which doesn't exist anymore any. Any size smaller than 70MM would be fine.

The specs are as follows:

Wing Span 23" Lenght 27"
Wing Area 193 sq/inch
MAX AUW is 3.5 lbs

The weight of the airframe with servos and Rx and covering is 12oz.

The plane will be light so I don't think I need a huge system. I'd like to keep it within a 3s pack, a 4S will be a tight fit.

I am looking at the Hoffman 69mm or the Eflite V15

So lay it on me What will work?

-Thanks for you time
Jason

Use the biggest fan you can fit.

There are a lot of choices in that range. The wemotech minifan 480 is the defacto standard in that size. The minfan pro is dynamically balanced and moderately priced. The WM400 is a moderately priced pusher capable of high power absorption and high efficiency. The HET 6904 is too. If you have the bucks Schubler us the best money can buy. If your cheap, a minifan knockoff can be had for under $10-be ready to do some serious balancing and checking - some have gotten out of center example though I haven't in the 3 I own. If you want a good (but fairly heavy) combination motor and fan have a look at the RCLanders. for a good 3s system look for a motor in the 3800 - 4200kv range for a minifan.

Problem with the Eflite is you need to use there motor since the fan requires a motor with a 4mm shaft and the standard for 28mm diameter motors is 3.17mm, other than that from what I've gathered it is a good fan just be careful when tightening the blade on as at least the original lot had a problem with them being broken easily.

I'm not very familiar with the Hoffman fans but I think they are aimed more at the high power end of the spectrum.

If you can get 150 Watts per lb minimum it should fly. If you want real jet performance shoot for 200w/lb minimum.

Thanks for the info! I decided to go with the Hoffman MMX-HW 60MM 650 watt they say it gives 2.2lbs static thrust on 3s. It puts my AUW to 1.5lbs. So it looks like Iam in good shape.

Any Idea of the amp draw at that thrust?

they recomend a CC 45 so it coudn't be more than 45amp right? This is why I lean towards nitro. You put a prop on if it fly like crap change prop

It should be, but if you want to get into electrics you're going to need a watt meter. Guessing is really bad in electrics because thing trend to burn up, sometimes literally.