Week 214 - Flap drive and engine start (attempt)

Hours to date: 1984.75

Another couple of weeks of (mostly) backwards progress I'm afraid.

I figured out that the throttle cable that was supplied with the kit was a solid wire type and more suited to a choke than a throttle. So I bought a new cable and installed that - the action was now much smoother and not catching on anything but when I looked up to the engine I found that the full travel of the lever in the cockpit was only giving 0 to 40% throttle on the engine.

So this will need a major mod to fix. I will have to remove the existing lever and put in a vernier type throttle - the same set up as Pete has. This will need a mounting point and cover built into the side of the cockpit. Joy!

When testing the fuel pumps one worked perfectly and when I tried the other one it worked for about one second before stopping and making a 'pop' noise. So one fuel pump has failed - I will see about getting a replacement sent.

Then I went to try an engine start for the first time and despite giving it a good crank it did not want to fire up.

As there was no popping or any un-burnt fuel in the exhaust pipe then this led me to believe that it was the ECU that was not working. The ECU controls both the ignition and fuel injectors. 

After a bit of fault finding I found that the fuse on the power supply to the ECU was blown. Upon replacing it and turning it on again the fuse blew again within one second so there is some fault in the wiring to do with the ECU. I've ordered a circuit testing device that is non invasive, that is, it can detect current through the insulation of the wire so no need to butcher my wiring to find the fault (we hope).

I also found a couple of small fuel leaks from the fuel pumps - where they connect to the joining tube and fine filter. The copper washers there obviously were not done up tight enough. I will sort that out when I replace the faulty fuel pump. Good to find these things before bonding on that lower fuselage panel methinks.

Let's end on a positive note shall we!?

I managed to bond in the plastic bearings for the flap drive and then rivet everything together. All works good! As I said last post I would not want to do this job after the fuselage base had been bonded on.

The order to do this in (after the plastic bearings are bonded in) is: 

1. Put wings on and align flaps to fuse with clamps - making sure that the flap pins are fully in the plastic bearings on the drive ends.

2. Rivet on the loose bearing end - access will only allow a couple of rivets at this stage but that is okay for the moment.

3. Once you are happy with everything drill and rivet the motor arm - again 2 rivets is enough here.

4. Take the clamps off and fire up the electrics. Test the flaps for operation.

5. If all is well mark the tube and arm position with a pen (not absolutely necessary as you have the holes already drilled to line it up again) then drill out the 2 rivets previously put in the arm - so the tube can now be rotated 360 degrees.

6. Rotate the tube in stages (by hand) to complete the drilling and riveting of the loose bearing end.

7. Align the tube again with the motor arm to your mark (and holes that were already drilled). Rivet those two holes and complete the rest of the drilling and riveting. 

8. You're done - go have a beer.

As you will have noted I pre-drilled both the motor arm and loose bearing end to make life easier.

Hopefully I will have a more productive next few weeks!

New throttle cable set at idle

Full throttle in the cockpit is only giving 40% throttle at the engine end - time for another mod!

All set up for the engine run - chocked and tied down to a tree.

Oil cooler inlet taped in place for (supposed) engine run.

Flaps working for the first time! See video below.

Flap drive bearing bonded in with flock.

Flap drive all done - tube riveted to motor arm

Loose end also now riveted to tube.

Few small leaks from the copper washers here - need to really nip these up tight.

Flap drive working for the first time - yes I finished the job in the dark!

First attempt at an engine start.

Week 212 - Flap drive, Control surface gaps and engine crank

Hours to date: 1964.5

Another few weeks of very little progress - too many social things going on this time of year.

Good news is the Push to talk is now working. It was such a simple fix - just plug in the earth wire! Doh! What is it they say "always look for the simplest solution".

On the Fuel Flow things are not quite as straight forward as my last post suggested. I contacted Dynon and they said they do not support the UL Power ECU fuel flow output and recommended the red cubes. However they then did say it is worth a try so we will see.

The Dynon already has a very good fuel computer in it which if calibrated should give very accurate fuel usage. The flow is based on engine revs.

Onto the flap drive.

Firstly though I had to make sure all the control surface gaps were correct. To do this Pete uses Nylon bushes on the pins. So that's what I'm doing. They are easy enough to cut down with a mini hacksaw to the required width.

I'm aiming for a 2mm gap on all surfaces.

We had a few nice days so I decided to wheel the Twister outside and get going on the flap drive again.

Good news is the flaps went straight on - sort of - the pins were only 1mm out vertically - so a little Dremel work on the flap tube hole saw this fixed and they went in easily. They were in perfect alignment horizontally.

When I was making the flaps I made the pins purposely too long. So then it was a simple case of reducing them down to the required length. If they are too short there is nothing you can do except start over with the flap which would not be good.

Next thing to do is wait for 48 hours of nice weather so I can bond in the flap drive plastic bearings - which has to be done outside for me as there is not space inside the garage to get both wings on.

Once those bearings are bonded the loose flap drive end needs to be riveted to the tube  and then the drive arm is also riveted to the tube. I am not leaving this off until after painting - as the manual suggests - I think it would be a major pain to rivet this when the bottom fuselage is bonded on! I'm not worried about the paint in the wing root as this will not be visible when the wings are on.

As all the wiring is now done I decided to fill the engine with oil and give it a crank over to get the oil through the system.

Due to my oil cooler mod and the length of the hoses it means I have about 600ml more oil in the system than a standard set up (3.5 litres) which I think is only a good thing as these engines don't have nearly as much oil as a Lycoming. It will help with keeping the oil cool.

It took a bit of cranking then checking the level - which had gone down. Refilling to Max and then cranking again until I got a reading on the Dynon of oil pressure. So all the air has been purged from the system and it should be good to go for an engine start in 2 weeks time.

I'm still not happy with the throttle set up and am changing that so will report on that in my next post.

Nylon bushings cut down with mini hacksaw

Gap of 2mm on Aileron

Bush in place.

Getting wing on for flap drive job

Add caption

Almost right - need to go up by 1mm or so on the tube to match the pins

Pins are too long on purpose - cut down in stages to fit perfectly

Fuse and flap do not line up here so a bit of an extension to the fuse is required.

Okay on the Starboard side though.

Flap/Aileron gap too tight here - now fixed with another bush

Video of Engine cranking.

Anequim update - records smashed

Did we ever doubt them?

They didn't just beat the existing records they smashed them!

Amazing results from what is a small team of students mostly (led by a genius aerodynamicist - Paulo Iscold).

I copy the text from their Facebook post below.


Ok, time to tell you guys some numbers.

We arrived here in Santa Cruz, Rio de Janeiro, last Tuesday and since then the work load has been huge! We've been working all day until 10PM and waking up at 3AM, Flying early in the morning and late in the afternoon and using the middle of the day and part of the night to do some improvements on the airplane or to re-configure it for the next flight. Our record flights started last Friday and until yesterday we had already managed 5 world records. What a way to fulfill our promise! These are the records (all C1a category):

1) Speed over 3km with restricted altitude
Previous record: Nemesis DR-90 - 466.83km/h (Jon Sharp)
New record claim: 521.08km/h

2) Speed over 15km
Previous record: Nemesis DR-90 - 455.8km/h (Jon Sharp)
New record claim: 511.19km/h

3) Speed over 100km
Previous record: W.Air Race - 389.6km/h (Richard Young)
New record claim: 490.14km/h

4) Speed over 500km
Previous record: VariEze - 387.4km/h (Klaus Savier)
New record claim: 493.74km/h

5) Time to climb up to 3000m
Previous record: Pushy Galore - 3min and 8sec (Bruce Bohannon)
New record claim: 2min and 26sec

So, yes, we got five world records and now we can call Anequim the world's fastest four cylinder airplane, delivered as promised!

Paraphrasing my friend, Paul Bonhomme, if we can say anything about this, it is teamwork, teamwork, teamwork! The Anequim project doesn't have sponsors, it has a TEAM! A team that is not afraid to face challenges, a team that is, always, willing to overcome difficulties, a team that doesn't mind extra work. Thanks to Catto Propellers, Sky Dynamics, Fibraer, Grove Wheels and Brakes, Alto Alumínio, Solid Works, Saber Manufacturing, Raphael Brescia, Brian Utley, and last but not least, all the students that spent hours working on the project, since its conception to now! I am sure it will be a mark for the rest of our lives!

Week 209 - Electrics and Fuel lines again!

Hours to date: 1945.0

As you can see by the hours I've done very little in the last two weeks. Been away for two weekends in a row. One of them was flying though so that's okay.

Nipped across to Le Touquet in France. Perfect weather for it too - it was the best visibility that I've experienced in the UK on the return leg.

I've now got the 12 hours needed for revalidation of my license. Just need to do 1 hour with an instructor and get my license signed and I'm good for another 2 years. Hope to be flying the Twister in less than a year though.

These last two weeks it's seemed like 2 steps forward and 4 backwards.

After doing some more research into the fuel flow issue I contacted the manufacturer of the 'red cubes' and they said I needed another module to connect to the two transducers. No one would sell me this module on it's own - they all come with a red cube and the price was $350 US. 

I decided to contact the UL power factory direct and ask about the output from the ECU marked - fuel consumption.

Here is what they had to say:


Hi Andy,

 Indeed, ECU has 2 different output signals . Up to you to make a choice which signal you use.

 Sorry, I do not know how to connect to dynon, please ask directly to dynon.

 Both signals give a nearly exact fuelflow. ( we checked it with measuring cups)


 Met vriendelijke groeten,

 Cordialement,

 Best Regards,

 Patrick Denorme

 ULPower Aero Engines NV


The red cubes are heavy, expensive and complicated so I've made the decision to remove them and use the ECU for fuel flow measurement.

So I've used the white and red wire which is for fuel consumption in Pulses/Liter - rather than the blue and white wire which is for Injector Pulses. This is connected directly to the yellow wire marked for fuel flow in the Dynon.

There is no info regarding the configuration with the Dynon - which wants a 'Pulses' figure inputting. I will contact Dynon and see what they say - I've already looked through their forum and can't find the information. I'll share it here when I get the figure from them.

In doing this I've had to re-do the fuel lines to remove the red cubes - the feed line is done and the return line is almost done.

It's kind of been a blessing in disguise as I've taken the opportunity to relocate the non-return valve in the return line which I put in the wrong place before.

It should be as close to the engine as possible to minimise the amount of fuel in the system that could be burnt in the event of a fire. I don't have room forward of the firewall so I've put it straight after the fitting behind the firewall.

I've also been working on the throttle connection - but before doing this I did some research. I phoned Pete and asked about his set up - which looked very complicated to me and also Mark of Galaxy Microlights - who is the UK agents for the UL Power engine.

Pete's reply to why his throttle was set up this way was - it looks more 'Aviation'. Mark's set up is much simpler - see pics below of both set ups.

I've decided to go the simple route as complexity for no reason is not a principle of good reliability.

I've had to make up a bracket which takes the throttle cable up a bit to clear the oil fitting behind - see pic. I've got a drilled bolt on order for the attachment point. Will post pics of that when it is done. It's that simple. Just make sure to leave a little movement in the lever at either end of the range so that you are certain you are getting both full power and a complete idle from the lever.

I've also made up some fuel lines for an engine run which I hope to do in the next month or so. 

The weather is looking good for this weekend and I'm not going anywhere so I will most likely get going on the flap drive job again.

Carbon bracket I made so throttle will clear the oil line fitting behind.

Fuel lines I made up for an engine run.

Check valve in Return line - repositioned to reduce amount of fuel in system in event of fire.

Mark's throttle set up. Simples!

Pete's throttle set up - complicated for no reason.

Week 207 - Electrics Cont.

Hours to date: 1933.0

As you will see below I'm getting on with the electrics. 

In fact there is not much more to do other than the fuel flow and a tidy up in some areas.

I'm still trying to figure out the fuel flow set up as things were not clear from the manufacturer of the 'Red Cube' FT60 fuel flow transducer. 

After contacting the factory direct it does seem that I was right all along to install 2 transducers (even though their literature disagreed with this). However I also need to buy a small module that takes the readings from each transducer and works out the difference before sending that information to the Dynon D180. This is because with the UL engine we have a return line and most of the fuel travelling through the system has not been burned up each time it passes the transducers.

Make sure you include a big ground lead from the case of the Dynon to your master ground as the Dynon needs this to work correctly.

After what seemed like hours I finally got the harness sorted through the firewall and fixed the firewall protection plate (I'd previously made up out of stainless steel) in place. Quite a confined space to work in both sides of the firewall but we got there in the end. The white goo is from the other passthrough kit and makes a fireproof airtight seal. As you can see I used a piece of firesleeve to wrap the harness before doing this.

I noted that Pete doesn't do anything here and has a big gap around his wiring harness which means that his firewall is not truly a firewall! No wonder he had smoke coming in the cockpit when his alternator cooling fan failed.

I finally got the top panel in yesterday and have switched a few things on. The Dynon, GPS, Radio and Transponder - which all work okay. The only thing that isn't working at the moment is the Push to Talk for the radio - so I'm trying to trouble shoot that now. The power for the iPad also works fine.

The Dynon is going to take a lot of configuring but I have made a start. All the temp gauges are accurate so far, reading ambient temperature and agreeing with one another. The sensors must be configured as they will almost certainly be set up wrong in the Dynon as default sensors. I noticed my oil pressure was reading 85psi but after I had configured the sensor correctly it dropped to zero.

With the fuel sender electric connection on the wings I've gone for the same set up as Pete, which is an automatic connecting device when the wings go on. The wing part of which needs to exactly align for it to work, so I've made a small plate out of carbon which I will bond to the wing when I put them on next. This way the wing part of the connection will be in the perfect position. A trough needs to be made into the wing root around the area where this plate will bond. All of that I will do when I get the wings on next time.

When I've finished all the electrics and hopefully the weather improves then I will switch back to the flap drive job which I got part way through last year.

Dynon remote compass all wired up.

Headset plug sockets all wired up and installed.

Big ground lead from the case of the Dynon.

Main wiring harness firewall passthrough.

Getting tidier...

Conduit and P-clip added to main harness from cockpit to firewall.

Firesleeve over main harness as it passes through the firewall.

Fuel sender electric auto connect/dis-connect. Carbon plate will be bonded to wing root.

Getting tidier underneath with spiral wrap and zip ties.

All fired up for the first time. Everything works except for the PTT.

Catto props

I'd love to hear this talk by Craig Catto.

Using a GoPro attached to the prop centre he is able to study airflow and refine the fences. An improvement to the prop improves the whole aircraft performance envelope (much as tyres are the most important component on a motorcycle or car).

It will be interesting to see if this catches on and other prop manufactures follow suit/copy.

New engine from Rotax

Announced yesterday at Oshkosh.

It looks like a real challenger to the UL Power 350iS, which is rated at 130hp. And I'm sure the UL would have a higher fuel burn and has a reduction in power with altitude being normally aspirated.

Week 205 - Electrics

Hours to date: 1910.75

Slowly making my way with the wiring. Quite enjoyable work this - no messy resin or carbon splinters.

As you can see below I have redone the hook for the canopy securing cable as I was unhappy with the screw in single post effort I did before. It seemed like it would pull out if the canopy were opened to it's full extent in a hurry. This new hook is rock solid.

With the wiring I started off in connecting mode and have now shifted to tidying mode before doing any more. The below pictures were taken in the connecting stage.

Canopy cable hook redone using unused part from canopy parts board.

First it has to get messy then it gets tidy.

Conduit and p-clips to come here.

Week 203 - Plenums cont.

Hours to date: 1888.5


Good progress this week. 

I'm now taking a day off during the week (when I can) and this seems to help with moving forward. Honestly I've been pretty frustrated with the slow speed of progress over the build of this kit but the end is in sight now and I'm redoubling my efforts to finish it by early next year. Hopefully it will be ready for paint by April/May. Then final fettling and test flying in June/July is the plan.


Onto the plenums.


After sanding the micro I still had to add a little body filler to fill in the pin holes and gaps in the micro. Once that was done I used duct tape as a release.


Then followed a tricky layup which seemed to take forever. 5 layers of carbon were used and laid up on plastic then cut out to a neat shape. My big mistake was not allowing for the fittings close to the edges - which stop the carbon from laying flat against the sides. If I were to do this job again I would remove anything close to the top edge. But it was too late as I didn't have access to the inside of the baffles as the foam plug was there. My mistake for not thinking far enough ahead again. 

I find things stick better when you apply a coat of neat resin to the plug early on in the layup - then by the time you are ready to put the carbon on the resin has cured a tiny bit and become quite sticky.


As it turns out things worked out pretty good anyway and only the back area is not great - although it will still seal air tight with a good application of RTV.


The duct tape release worked well and with a couple of plastic wedges I was able to remove the plenum tops with no trouble.


Slow steady pressure is the idea here - don't force things too much.


As you can see below the plugs came out in one piece from the baffles - so if anyone wants to borrow these to layup their own plenum tops then give me a shout. They will save you at least a days work.

All that was left to do was trim the plenum tops out and then fit them with 4mm nut plates all round. I used 14 on the Starboard one and 13 on the Port one. The odd spacing is due to obstructions on the inside and or access from the outside to drill. There will be quite a lot of air pressure inside here at VNE so it's best to make sure it is properly secured. I read a forum in the USA about building a plenum for an RV8 and the forces measured were very high for the plenum. If I remember it right it was over 200 lbs at 200knots. Just think what it does to the top of your cowl if you only have baffles - no wonder they are so inefficient.

The 5 layers of carbon is just right - very strong but with just a little flexibility so the nut plates pull the edges in tight.

Next job is installing the top instrument panel and finishing all the wiring.

Micro and body filler sanded smooth - all ready for duct tape.

Duct tape added.

5 layers of carbon layup.

Plastic wedges help with releasing from the plug.

Foam plugs released easily and in one piece.

Trimmed out. Now for some nut plates.

Port side done. (RTV not added at this stage).

Starboard side done.

Nice flush profile