18 replies to this topic

[Thanassis]

We know that Renault is developing an engine, which is at 111 degrees between the cylinders, right? I have read on this BB that this is considered quite an innovation, and as soon as Renault solve some problems they have regarding vibrations, this engine will be really good.

Now let me take it a little further. What if a team developes an engine which has even greater angle, let's say 180 degrees?

Provided that this second engine has no problems (or the team manages to solve them), is it going to be better than today's engines at 90 or less degrees?

Best regards

[Peter Perfect]

I don't have enough knowledge to answer but will ask a similar question:

Why does a larger V angle mean more vibration?

Actually I can make a guess at the subject question.
To minimise vibrations and reduce any chance of the engine falling apart the enigne itself would have to be stronger=>bigger and heavier.
I think it would depend on if they could strengthen the engine block without increasing the weight significantly. If they could then a lower CoG would be an obvious benefit (assuming they could package the exhaust and stuff well)

[Marcel Schot]

The main problem of flat engines is their width. Even in the days when Flat engines were previously used in F1, there were very few teams believing that the benefits would overcome the deficits. Today F1 cars are by rule a lot less wide, so I doubt if it's technically possible at all (not that I'm that technically educated, just a gut feeling).

In the past, I've written a little more in the F1 FAQ: http://www.atlasf1.c.../nov22/faq.html

[desmo]

The assumption that wider V-angles are necessarily more vibration prone isn't true. Good primary balance can and an even firing order for a V10, for instance, be had at 144 degrees. Boxers aren't used for packaging reasons primarily I believe. One must either raise the engine or use a novel port design such as routing the ports between the cams to keep the exhaust plumbing from interfering with the undercar aero.

[nzkarit]

Would the boxxers lower the center of gravity?
That would have some benefits.

[Spot]

Back in 1980, Ferrari discovered the problems with a flat-12 design. The width of the engine across the bottom of it prevented the car from having truely effective venturi, which is the main reason it was nowhere that year. Those with narrow V8's had more room to bring up the underside of the venturi earlier and steeper, thus creating more downforce.

With todays diffusers, and the coke-bottle shape read-ends, the same problems would apply, i.e. poor aerodynamics.

[obi-one]

Originally posted by nzkarit
Would the boxxers lower the center of gravity?
That would have some benefits.

The boxer design has a lower center of gravity but since they are designed with the exhaust exiting the bottom of the block the entire engine must be raised. Therefore they end up with a higher center of gravity in cars so low to the ground and with Venturi ground effects.

[Croaky]

I think I know how Renault are getting round the packaging problems of a wide-angle v10. They're probably using a flat-head sidevalve design... It frees up space for their new de dion rear suspension. Now that the leaf-sprung beam front axle works, their next project will probably be an audacious attempt to extract downforce from those big flat things at the front and rear of the car.;)

[imaginesix]

HA! Good one

[marion5drsn]

Just found that Lycoming makes a 180 degree block 8 cylinder and have written them to find out if they sell a manual that doesn't cost a small fortune. This is very interesting as I was just making a series of sketches to see if it would even work. It's aircooled and is 720 cu.in. Taylors book has an evaluation of the vibration. This type of engine must be about the only type that Ferrari didn't make. It boxes only to a limited degree. M.L. Anderson
EDIT; the boxing of this type is not adjacent to whichever cylinder is at question but does box between other cylinders that are not adjacent. M.L. Anderson

[desmo]

This Porsche 908 was a very successful flat-8 design. Factory blueprints of this engine are, I am pretty sure, available for purchase on the web. Try Googling "Porsche 908 blueprints" and you can find the source.

[BRIAN GLOVER]

Renault claims, or the rumour has it that their engine is 111 degrees. More like 96 degrees. Loss of beam strength is a problem and mounting suspension components requires external metal metrix beams which actually makes the overall package ligher and stronger. The flatter the engine, the worse this problem is. Fortunately low aspect ratio tires simplifies suspension design and packaging. The fact that Renault still billet major external components(spy photos), indicates problems in development. Dont scoff at Renault, they have been there first before. CG is not as important than AD. The intakes come from the side pods reducing high drag above drivers head. Air is split to radiators in side pods.
V10s with flat ignition timing comes with a lot of vibration. so there is not an 'ideal' v, such as V6s and V12s and even V8s. If the FIA decided that there was no limit to fuel allowed in the pit lane, manufactures would revert to V12s, now illegal.

[Darren]

Real designers use flat 12s and fans.

[Jhope]

Renault are noe deniying that they ever had a V-Angle anywhere close to the 111' or even 110' mark.

[marion5drsn]

Brian, please explain the "flat" ignition timing you speak of as I don't recall ever seeing this phrase used in this way before. Yours, M.L. Anderson

[BRIAN GLOVER]

Howdy Marion,

Simply put, it is a throw sequence and firing order for power instead of smoothness. Ferrari designed bothe the F360 engine and the Maserati 3200 and 4200. The F360 has the flat firing order.

Originally posted by marion5drsn
Brain, please explain the "flat" ignition timing you speak of as I don't recall ever seeing this phrase used in this way before. Yours, M.L. Anderson

[marion5drsn]

Desmo. I’ve been working on the Lycoming 180 degree block engine and the firing order that is in their Direct Drive Aircraft Engine Manual Page # 4- 7. This part of the manual has a Figure 4-11 Ignition Wiring Diagram that shows the dual Ignition wire/Magneto layout plus the cylinder numbering system. Starting at the front of the engine and on the right side is number #1 cyl. followed by 3, 5 & 7 on the left side is # 2 at the front followed by 4, 6 and 8. The diagram also shows the two magnetos and their direction and the position of # 1 cyl. spark plug wire. Will try to send you the diagram I made of this, as the lines in the diagram in the manual are too fine to make a good copy.
One must always keep in mind the fact that aircraft engines in general turn to the right (Pilots view CW) whereas auto engines turn left (Drivers view CCW). This is possibly due to the fact that some old aircraft engines cranked from the back.
One thing that struck me was the crudeness of the timing of the spark system (Dual Magnetos) that seems so out of date in 2001. Most of the engines seem to have fuel injection. But then again aircraft engines need dependability as a first and last requirement.
The Firing Order is # 1 – 5 – 8 – 3 – 2 – 6 – 7 – 4. This is given above and to the left of the diagram and also in others parts of the Manual. The spark plug wires and so forth follow the same numbers.
The crankshaft is 28.226” from the back end of the crank to the forward thrust face, a very long crank, 720 cubic inches, or 11.8L. Am now in the process of trying to figure out just how many firing orders there would be if Chevrolet made a 180-degree

[Ben]

Not being an engine guy myself I could be chatting s*** but it was my understanding that a lot of the Italian flat 12s were originally aero engines. They were mounted in the wings (hence the need to be thin) and the problem of porting wasn't there because you could duct both sides of the wing.

Ben

[marion5drsn]

Ben, I’ve finally got around to some checking on the belief that the Italian aircraft had Opposed cylinder engines in H. Smith’s book Aircraft Piston Engines. The Opposed engine was developed by Duthiel-Chambers in 1905. Very few of the engines were made in Italy. Most were 2,4,6 and 8 cylinder air-cooled. Probably more opposed aircraft engines were made in the U.S.A. than all other countries combined. Remembered Lycoming, Continental and Franklin were all in the U.S.A and Porsche, Corvair and Subaru are not truly aircraft engines altho used as such many times. Yours, M.L. Anderson