It'll Never Fly - The Story Of A Not So 'Mini - Whizz'

Mini Whizz Designed by Brian Cooper. Issued free with RCM&E magazine. Volume 42 Issue 7 June/July 1997

Picture from RCM&E Mini Whizz article 1999

Mini Whizz Specifications. Span: 36" Twin Tail Delta Engine: Thunder Tiger GP .15 Propeller: Kavan 8" X 6" Fuel Tank: Blue Top Slek Radio: Hitec HFS-04MI+ Control: 3 x JR 507. Weight: 2.5lb ~ 1.1kg

I arrived to find Choddy hard at work in the model workshop. He was building something very flat looking and I sat and read the article in RCM&E to see what had got Choddys attention. The Mini Whizz seemed like a sporty sort of model and without a batch of wing ribs to cut (being a novice myself, building from a plan was quite a step) I had only flown my trainer and this seemed like a fun sort of thing and I already had a bunch of bits I would need.



"It'll never fly with that little engine!!"

The scathing words of my model flying instructor will never be forgotten when he first held my finished 'Mini Whizz' Delta-wing.
"What did you make it from, an old wardrobe?" He said, joyfully.
His words cut deeper than the worst propeller accident ever could.

I was devastated.

Weeks of odd evenings I had spent constructing that wing, rubbing down, filling, sanding, sheeting, sanding ....
more sanding....
and finally....

I covered the whole thing with Alu-Clad (a sticky back aluminium foil from Flair)




It looked the business. but then I weighed it!!

ULP!! 3.5lb ~

only about a pound over weight then.
But that was without a reciever battery or fuel .... oh god, it never will fly at this rate. The engine of choice was a Thunder Tiger GP15 ABC two-stroke, originally destined for the BAE Hawk I had bought the plan for. The compact engine soon became the latest bit to be 'robbed' from the Hawk parts box. It was completed and ready to run about midway through November but after a failed attempt to start it on a freezing cold day it was left until ......

The last day of the twentieth century was upon us and I was offered a last chance to fly this millenium so I grabbed my trainer and transmitter.
" Bring the plank ''said someone...
so I grabbed the Delta and off we went.
As it was a mild tho somewhat misty day the TT GP15 started and ran very well. A quick control surface check and Grot (my instructor) threw it into the air ......

After a faltering second it got it's stride and flew ~ YES it actually flew.



And how it flew. The small engine became apparent when trying to go vertical. It stalled very quickly so to gain altitude a series of climbing passes were needed. The flight didn't last long, maybe 3 mins then the engine died but a safe landing (considering it has no undercarriage) was performed by Grot.
My detractors had been silenced ~ Grot couldn't wait to fuel it up and do some more.
Here's where the first problem arose. The fuel tank was still half full. How could this be? ~ a second flight was carried out. Same thing, after a bunch of slightly aerobatic maneuvers the engine faltered and died, but still half a tank of fuel (??) To counter this problem, the nicad RX pack was moved below the fuel tank (thank heavens for Velcro) to raise the fuel feed pipe to closer the height of the carb. It worked. The next time the plane returned the fuel was all gone.
This final flight had proved to be a great deal of fun for Grot using the Delta's lack of climb as an aerobatic novelty.

I took my first flight today with the Delta ~ from now on referred to as the 'Scolded Cat'



And I showed off. I have spent many hours on a radio control flight simulator, which doesn't make for a very 'real' flying environment it does teach you how to use the control sticks properly. So I put what I had learned about some of the aerobatic manouvers to use. Snap rolls, loops, half loop barrel rolls and almost a flatspin. It was falling near vertical at this point so I pulled it out for a low pass instead of trying to continue the spin. I felt much more at ease than with the trainer as I had built this plane and if I destroyed it ~ so what!

Grot then made me land it because I had run out of fuel and for my first landing it was as little drama as I could have hoped for and it flaired into the long grass without so much as a twitch.

OH!! WOOOAAA!! OOOOH!! CAREFUL!! OOOOPS!!

These are the printable exclamations from the coversation that took place as the Scolded Cat was whipped onto it's edge by the wind. Being a zero lift flat flying wing, if the delta becomes side on at 90 degrees to the ground it falls like a piano. The only bright side of this event was the plane was only 6ft off the ground when it happened. It landed edge on quite hard but suffered only slight seperation of the fus' from the wing, a broken control surface hinge and a split exposed wing spar.
Not much drama at all.

The desision had been made.
The Thunder Tiger Pro25 has been ordered. With over 3 times the power of the GP15 this new engine should provide more than enough pull to make this cat shift!!

A heavy landing short of the strip caused the GP15 & the firewall to detach so the plane was put away while I waited for the engine to arrive and other projects such as the Topic 400 Glider and T-33 Ducted fan planes were finished.

Cat with it's nose out of place	It's heart and lungs laid out.

Time to look again at The Scolded Cat.
The new engine a Thunder Tiger Pro 25 was ready to be installed.

Old GP15 on left Pro25 on right.

Quite a difference in size and power but only a slight increase in weight.


New engine on bench ready to be installed. And finally in place in the nose.


New firewall in place, beech braces used.

Installed and ready to test, fuel tank filled, all controls checked, trimmed and sub trimmed.
Fitted Glow Starter and after 2 effortless turns on the prop the Pro25 fired into life.
First thing I noticed was it is a fair bit noisier than the GP15.
First tests without a hitch. A flight round the field showed it to be too tail heavy and landed quickly. With nothing to ballast it down with we headed home happy it worked.

A couple of failed attempts to start the engine soon put me off again. I wasa little disappointed with the engine at this stage and for the rest of the summer I parked the Scolded Cat in the loft and all but forgot about it as I was bitten by the electric bug.
Topic 400, T-33 & Pico-Jet Combat all saw plenty of action.

Time passed ......

I decided to celebrate the anniversary of my first flight and took the Scolded Cat to Bumpy Green to blow out the cobwebs. The engine sounded a little spluttery when throttling up but sounded ok once on full bore. I heaved it into the air and away she went. I circled wide then realised the engine was dying and tried to turn back from the small copse of trees ~ down she went ~ into the trees it seemed. A few minutes later Grot and I approached the area it looked like it had gone down in. We looked around in the woods and found nothing and could see the back of the tree line ahead. I spotted cows in the field and was filled with horror as I imagined finding some poor creature sliced in two by a fast falling, aluminium coated Mini Whizz! (Imagine an old fashioned guillotine blade falling on a happless victim and you'll get the idea) At this point Grot pointed out it might have been an idea to bring the transmitter so I could move the sticks and listen for the model when there it was, in the soft long grass about 6ft from the fence, and not one decapitated cow in sight. I dared not look and picked it up and carried it away without so much as glancing at it.


It must have landed nose first as the spinner screw holes were full of mud and the firewall was split and pushed back.



A hefty dollop of epoxy and a handy clamp and the firewall was repaired and secured. Another length of beech was added behind to replace the split fillet. Once set the front end was solid as a rock. It did however shock the hell out of me (the loss of control that is not the repair) and I was too nervous to fly it again. I went back to my electric friends who had never let me down in such a way. Back up the ladder she went and carefully placed at the far side of the loft to be decommissioned.

Fetching the Scolded Cat from the loft once more, with a mind to removing all the parts I was looking at the engine and unscrewed the carb needle valve and found no rubber seal. This may have caused the problems encountered so I put a new one in place and tested the engine in the garden. It sang to itself like a choir of noisey things. The following day I carted it along to Bumpy Green and gave it a tank full of fuel, checked the battery and the balance and fired her up. A quick tune on the needle after a few minutes of warming up and she responded instantly on throttle. Rates set to 40% for the launch and away she went. A few laps of the field to get used to her and make sure it wasn't going to die out like last time and was rewarded with a good ten minutes of flight. It landed nicely and I refuelled and relaunched. This time Choddy had the video camera out (see Cinema for movie) so off came the reduced rates and I flew numerous high speed low passes, looped and rolled more times than I can recall and generally had the time of my life. This engine in a light weight Mini Whizz would be nothing short of ballistic.


For a model far too heavy for it's size, and quoted as 'the plank' 'the wardrobe' and 'it'll never fly' it didn't do so bad.
The Scolded Cat is now fully retired but left with all horns, control snakes and engine mount in place in case I ever feel the urge to take her up again.

The First	& The Last

Final Spcifications. Engine: Thunder Tiger Pro .25 Propeller: Graupner 9" X 6" Fuel Tank: Red Top Slek Radio: Hitec HFS-04MI+ Control: 3 x JR 507. Weight: 3lb 12oz. ~ 1.75kg

Article by Chinman from Bumpy Green Model Aerodrome
12th September 2001