Ripmax 'Bullet'

 

A 'NO HOLES BARRED' REVIEW OF THE RIPMAX BULLET

 


When the time came for me to buy a new weekly hack, the requirements were mainly:-

It would be powered by a .46 sized engine.

It would have a tricycle undercarriage so taxiing and keeping it on the ground after landing, in case it was windy, would be made easier.

It would fit across the back seat of the car.  This was to save me having to empty the (always full) boot of my car, something I don't like to do if the weather might prevent us from flying.  The tricycle undercarriage requirement narrowed the choice down , but after reading up on the retro Ripmax Bullet,  I quickly decided that was 'THE ONE'.

 

THE BUILD

My method of building is, after working through the day, coming home for tea then doing a few repairs or the books - then hopefully that leaves time to assemble a few parts of the plane before bedtime.

 

 

This worked out very well with the last two planes which were the Hanger 9 Showtime and the ARTF Acrowot.  The Bullet however was the wrong plane to use this method as each and every part required so much work, that to get even one section finished was an achievement.  The Bullet has to be the worst ARTF that I have ever bought!


To give you an example, the three wheels supplied are all the same but the front nose leg uses a heavier gauge wire.  Fitting the front wheel required enlarging the hole. The clevis for both the rudder and elevator could be pulled off the push rods without too much effort.  The covering combined with the trim are so thick that when removing it to fit the tail plane and elevator it was near impossible not to start cutting into the soft balsa.  The cowl overlaps the fuselage by 2mm and the instructions say screws are to be inserted in this area to retain the cowl.  The wing required a fair amount of trimming to sit neatly in the fuselage and alignment of the tail plane was quite a bit out.  Get the picture?

 


Perhaps I am nitpicking or I got spoiled by the ease of assembly with my last two planes but this was a real pain to assemble.

The building started with joining the wings, and the spar was one of the best fitting I have seen, but when fitting the wing to the fuselage there was quite a lot of trimming needed to get it to fit correctly.  Cutting away the trim with a knife for the two servos, I found it hard not to start cutting into the soft balsa so I used a soldering iron to melt away the covering. This was great for not going into the balsa but did result in a slightly jagged edge.  After enlarging the holes for the servos to fit, it was time to fit the push rod and thinking that the clevis was not a great fit, I give it a tug and the pushrod came out quite easy.  After testing the rudder and elevator push rods, one end of each was okay but the other ends again were faulty.  I sent an e-mail to Ripmax explaining this and their reply said they would look into this and asked how many I required.

A 'result' I thought, but after waiting two weeks I had to send another e-mail which did the trick with them sending me the correct parts.


Cutting away the covering for the tail plane and fin, I again used the soldering iron. 

 

 

Checking alignment of the tail plane showed that it was too far out to leave and required a fair amount of sanding and packing to straighten it up.


The fin, going buy the instructions, goes through the slot in the fuselage and sits on top of the tail plane.  As the balsa was so soft and also that the section at the very rear of the fuselage tapered to about 5 millimetres in height this didn't appeal to me.  As you can see in the picture, I inserted a tongue into the fin and cut a hole in the tail plane to interlock the two. Hopefully nothing will part company when I try a snap roll!

 

The servo tray and other areas inside the fuselage needed more glue (in my opinion) but due to the complexity of build around the nose section, I could not get any glue onto the firewall.  Trying to insert the tank was eventful because the tank itself rests on three formers which are a neat fit. Then for some reason the fuel lines have to drop about an inch to exit the firewall.  This would not have been such a problem with the engine not fitted but was a bit of a fiddle with the engine in place.


The cowl was next.  Due to the small overlap onto the fuselage, I fitted three blocks of wood onto the front of the firewall and used these for the screws to secure the cowl.


Centre of gravity check and WOW, surprise, surprise - it was a mile out!   I'm not sure of the exact weight I had to attach but must have been four or five ounces!


I took the plane with me to Kirkistown for it's maiden flight but due to twenty five (plus) mile per hour winds, decided that it was not the day for a maiden flight (who in their right mind would fly in those winds!!!).

Two weeks later and conditions were great.  Stewart was wanting to take some video of the plane, so while he was getting organised I started the engine to check things out.  All was great with the OS 55, until I went to full throttle, then all hell broke loose with the cowl flapping around and rubbing against the spinner.  My first thought was that a screw securing the cowl had come out but after checking, I could not find any reason for what had happened.  Trying it once more the same thing happened again at full throttle, hence the lack of a cowl in the video.  I will add an extra bracket to the bottom of the cowl to see if this is were the problem is.


THE FLIGHT


Out onto the runway and hopefully the Bullet will fly so well that all the hassle of this build will have been worth it!  Take-off, and just a few clicks off up elevator and left aileron and it was flying smoothly, very smooth indeed!  In the turns it reminded me of a low wing trainer that, when giving inputs, the plane was responding by saying, okay, okay. What's your hurry.  I'm turning!  Although not advertised as acrobatic, I did expect a little more from this plane.  Having said that, it was obvious while landing that it needed less lead up front, so perhaps doing that and cranking up the throws, things will improve?  Think I will stick to Hanger 9 and the like in the future.  You do get what you pay for, as they say.

 

 

Dennis

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