3DHS 84" Bigfoot Build Log

[SnowDog]

Well, I finished the build...required a few late nights last week. :|

Here's the final set of build pics, including the air tunnel exit...this setup makes sense to me.
(I added the angled balsa sheet to close off the tunnel here and direct air out the bottom...the tunnel actual goes back another former or two. I think this is what Joe meant when he said use an exit in the tunnel, not behind it. Putting a hole in the lower fuselage behind the end of the tunnel won't really help airflow at all.)




I reinforced the top hatch...without something sturdy there,
I didn't give that hatch more than three flights.


Here's my hatch latch:




RX mounted on pull pull ruder structure:



ignition battery: switch location


final configuration of internal components:


No pictures, but I assembled the wing struts as my last step.

This was a royal pain, not because of the struts, but because the blind nut holes in the fuselage WERE NOT MARKED!!!

I had to go "digging around" using the pics in the manual for the rough location. I did have to bend the tabs on the wing struts to get them to "fit" the curve of the wing, just as the manual specified...but that was not a big deal.

Ok it is ready to maiden!

 

[SnowDog]

Here are the pics from just before the maiden flight:

 

[gyro]

Here are the pics from just before the maiden flight:

View attachment 18403View attachment 18402View attachment 18401View attachment 18404View attachment 18405

Great job, looks awesome!

 

[SnowDog]

Bigfoot Maiden

Well, it was pretty windy yesterday (10-15mph) but since we're running out of decent flying days up north, I decided to give it a try.

Preflight went fine, OS GT33 started up great (it has been run in other airframes and is fully broken in). Decided not to use any flaps until I got a feel for how the plane flies. Takeoff into the 15mph wind was smooth. Made a circuit of the field and discovered that turns needed plenty of attention to detail...definitely required rudder and should have included opposite aileron as well. On the second circuit of the field, I pulled the throttle back a little too much going into the crosswind leg, and as it headed around, the left wing dropped hard. I pointed the nose down and shortly thereafter firewalled the throttle but I did not have enough time or altitude to recover from the stall/spin. She went down into the cornfield. After recovering the plane, the right wing was basically torn from the plane and the right horizontal stab was knocked off. The left wing had minor damage, the rudder appears to be fine, the left stab needs some repairs, the cowl has some scratches on it, the fuselage damage is limited to the holes where the blind nuts for the wing struts got pulled out when the right wing came off at the time of the crash.

The manual is very clear about this being a different kind of airplane than other 3DHS aircraft. Unfortunately I didn't realize how quickly the wing would stall, and turning in that kind of wind merely made the problem worse. I will need to replace the right wing; I believe all other damage is repairable given enough time. I will have this plane flying again!

That being said, let the following video be a warning that perhaps can save another novice Bigfoot pilot from making the same mistake that I made.

[video=youtube;Q9hfoBwF5Vg]http://www.youtube.com/watch?v=Q9hfoBwF5Vg[/video]

Lessons learned:
keep the speed up...anything less than 1/3 throttle requires flaps, even on take off.
rudder and cross-aileron compensation is required in turns
ditch the Sullivan tires...they are way too heavy.

I'll be back once repairs are completed!

 

[3dNater]

Bummer on the crash Mike but it sounds like the damage wasn't as bad as it could have been. Good job minimizing it.

 

[kerwin50]

Yeah snowdog I just finished up a conversation about stalls is a crosswind leg in another thread. I too have lost a few planes due to this. It seems the crosswind are the ones that will really tend to bite you.
I now always try and add plenty of throttle on a turn in a down wind cross wind

 

[Tesla540]

Sorry about your crash. That always sucks especially on a maiden. Was your CG on the nose heavy side? The reason I asked is, it looks you are using the Dubro 6in tires. I read in another thread they are really heavy.

 

[SnowDog]

Sorry about your crash. That always sucks especially on a maiden. Was your CG on the nose heavy side? The reason I asked is, it looks you are using the Dubro 6in tires. I read in another thread they are really heavy.

Yes, thanks for the condolences. The CG was on the nose heavy side...those Dubro 6in tires are very heavy...they will not remain on the plane as I go about making repairs...they will be replaced with the 5" Kavan wheels which are much lighter.

 

[SnowDog]

So I decided to survey the damage from the crash...here's the pics...I'll let them speak for themselves:
















After looking at these pics, I'm actually impressed at how little damage the fuselage sustained. The right wing will probably be replaced, but I think the rest of the damage is repairable.

 

[Plowboy]

Thank you for having the decency to catch that on video! And I know you realize that the plane will fly much better now that you've taker the pesky newness off of her!!